A theft-deterrent system for a vehicle includes at least one detecting unit that detects information on damage of the vehicle including vehicle theft or vandalizing of the vehicle, at least one prevention unit that executes a preventive measure against the damage, a situation identifying unit that identifies a situation of the damage based on order of detection of the information, a degree-of-danger judging unit that judges a degree of danger based on the situation, and a theft-deterrent control unit that selects and controls the at least one prevention unit corresponding to the degree of danger to execute the preventive measure against the damage.