Electric circuit

A vehicle safety device (100) installed in a hybrid electric vehicle or an electric vehicle is provided to be capable of interrupting a current supplied from a direct current power supply (11) to an electric heater (5d) via a supply line (12). The vehicle safety device (100) includes first interrupting means (20, 22) adapted to set the supply line (12) in an interrupted condition when a temperature of the electric heater (5d) reaches a first set temperature and second interrupting means (30, 31, 32) adapted to set the supply line (12) in the interrupted condition such that the supply line (12) cannot be returned to an energized condition when the temperature of the electric heater (5d) reaches a second set temperature that is higher than the first set temperature.