Section 17 BNS: Act done by a person justified, or by mistake of fact believing himself justified, by law

Bharatiya Nyaya Sanhita, 2023

Section 17 BNS at a Glance

Section 17 BNS deals with act done by a person justified, or by mistake of fact believing himself justified, by law. It replaced Section 79 IPC on 1 July 2024.

Punishment

None. Section 17 BNS creates no offence.

IPC Equivalent

Section 79 →

Section 17 BNS Bare Act Text

17. Act done by a person justified, or by mistake of fact believing himself justified, by law

Nothing is an offence which is done by any person who is justified by law, or who by reason of a mistake of fact and not by reason of a mistake of law in good faith, believes himself to be justified by law, in doing it.

Illustration

A sees Z commit what appears to A to be a murder. A, in the exercise, to the best of his judgment exerted in good faith, of the power which the law gives to all persons of apprehending murderers in the fact, seizes Z, in order to bring Z before the proper authorities. A has committed no offence, though it may turn out that Z was acting in self-defence.

Source: Section 17, Bharatiya Nyaya Sanhita, 2023

Section 17 BNS in Simple Words

Section 17 of the Bharatiya Nyaya Sanhita (BNS) protects a person who does an act when he is justified by law in doing it, or when, by reason of a mistake of fact and not a mistake of law, he believes in good faith that he is justified by law in doing it. The key point is that any mistake must be about facts, not about what the law allows. If a person honestly and with due care thinks facts exist which would make the act legally justified, the act is not an offence even if those facts later turn out to be different. This section often applies where someone steps in to stop what appears to be a crime, as in the statutory illustration of seizing a person who appears to be committing murder.

It does not protect a person who knows the facts but misunderstands the law. In practice, this provision is a general defence that defeats criminal liability where the act was either actually justified by law or done under a good-faith mistake of fact as to legal justification.

Ingredients of Section 17 BNS

  • The act is done by a person who is justified by law in doing it, or who believes himself to be justified by law in doing it
  • The belief arises from a mistake of fact and not from a mistake of law
  • The belief is held in good faith

Punishment Under Section 17 BNS

Imprisonment

None. Section 17 BNS creates no offence.

Fine

None.

Section 17 BNS is a General Exception. It has no entry in the First Schedule to the BNSS.

Example of Section 17 BNS

In Jaipur, a shopkeeper, Dinesh Mathur, sees a man running out of a neighbour's house with a bag while a woman shouts that he is a thief. Dinesh holds him and hands him to the police. It turns out the man was the owner's brother taking his own bag. Dinesh made a mistake of fact, honestly and with due care, so under Section 17 BNS what he did is not an offence.

When Section 17 BNS Does Not Apply

  • The mistake is a mistake of law and not a mistake of fact
  • The person does not hold the belief in good faith, that is, with due care and attention
  • The act is not one which the law would have justified even if the facts had been as the person believed

Section 17 BNS in the IPC (Previous Law)

Section 17 BNS replaces Section 79 IPC from the old criminal code.

Section 17 BNS keeps the exception in the same words.

View IPC Section 79 →

FAQs on Section 17 BNS

When does Section 17 BNS protect a person from criminal liability?▼

Section 17 BNS provides that nothing is an offence which is done by any person who is justified by law, or who by reason of a mistake of fact and not by reason of a mistake of law in good faith believes himself to be justified by law, in doing it. Both actual legal justification and a good-faith mistake of fact as to legal justification are covered.

Is a mistake about the law covered under Section 17 BNS?▼

No. Section 17 BNS protects only a mistake of fact, not a mistake of law. If a person knew the facts but wrongly thought the law justified the act, this section does not apply.

What does the illustration to Section 17 BNS show?▼

In the illustration to Section 17 BNS, A sees Z commit what appears to A to be a murder and, exercising in good faith the power the law gives to all persons to apprehend murderers in the fact, seizes Z to bring him before the proper authorities. A commits no offence under Section 17 BNS even if it turns out that Z was acting in self-defence.

How does Section 17 BNS differ from Section 14 BNS?▼

Section 17 BNS applies where a person is justified by law in doing an act, or in good faith believes by a mistake of fact that he is justified by law in doing it. Section 14 BNS applies where a person is bound by law to do an act, or in good faith believes by a mistake of fact that he is bound by law to do it.

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Disclaimer: This is for informational purposes only. Always consult a qualified advocate for legal advice.

Sources: Bare Act Text, Bharatiya Nyaya Sanhita, 2023 · Last updated: 16 Oct 2026 ·