An anti-theft structure for an electronic control unit which includes an electronic control unit including assembly brackets mounted on both sides thereof and connector mounting grooves formed in an upper portion thereof to be spaced apart from each other; connectors coupled to the connector mounting grooves, and including connector coupling portions therein; and a safety bracket including side coupling portions on both ends of the safety bracket, the side coupling portions being engaged with assembly brackets, and bracket coupling portions corresponding to the connector coupling portions and the bracket coupling portions being engaged with the connector coupling portions.