PURPOSE: To allow the safe control of an engine by reliably perform the start and stop of the engine with only the on or off operation of a start/stop switch and performing various processes with the action of a timer means in time division during the operation.

CONSTITUTION: After a main switch is turned on, a CPU 1 monitors the action of a start/stop switch 32 and judges whether an engine is to be started or stopped with reference to the rotation index value calculated from the rotation detection pulse 1 and controls the engine according to this judgment result. Output signals of a battery liquid specific gravity sensor 31, an oil level sensor 33, a current transformer 41 to detect the load current, a fuel gauge potentiometer 42, etc. are inputted to the CPU 1 for arithmetic processing, and the battery liquid specific gravity, oil alarm, used power, fuel remainder, and output frequency information are displayed on various display means 61W65. This display control is performed in time division by the action of a timer means.