PURPOSE: To reduce the size of a device by centralizedly controlling an engine control which requires high speed processing and an electric equipment control for which low speed processing suffices, by means of one control device and switching to said engine control when a large variation occurs in the engine operating condition while said electric equipment control is being carried out.

CONSTITUTION: An engine control means 24 which controls the fuel injection, etc. in accordance with the operating condition of an engine 35, and an electric equipment control means 26 which controls the operation of each electric equipment 37, etc. while detecting the using conditions of these electric equipments 37, are provided. These control means 24, 26 are switched and operated alternately and repeatedly. A sensor 11 for detecting the operating condition of the engine 35 is also provided, with its output being inputted into an interruption signal generating means 13. And, when a large variation is detected in the operating condition of the engine from the output of the sensor 11, an interruption signal S1 is generated from this signal generating means 13, causing the electric equipment control 26, if this means is being operated, to be immediately switched over to the operation of the engine control means 24 through a switchover means 28.