PURPOSE: To operate an engine, even when a door is opened, by providing such a control means as actuating an accelerator interlock means in an open door condition as well as after the start of engine operation, upon receipt of signals from an open door detection means and an engine operation detection means.

CONSTITUTION: An accelerator interlock mechanism 10 is connected to a motor 1 and, then, to a power supply 13 via the contact of the first relay 11 and a key switch 12, and driven, when the key switch 12 and the first relay 11 are turned on. The excitation coil of the relay 11 is connected to the power supply 13 via the contact of the second relay 14 through the key switch 12. This excitation coil of the relay 11 is, on the other hand, connected to a door switch 16 and a door lamp to be turned on when a door is opened, via a wraparound prohibition diode 15. According to this construction, the contact of the first relay 11 is turned on and an accelerator interlock is actuated, when the door is opened with the second relay 14 in operative state.