To provide a performance measuring device for determining whether a trouble of an engine is caused by a metering oil pump or not and determining the performance of the metering oil pump, and also provide a device for controlling the supply of oil for separated oil supply into the combustion chamber of a rotary engine when the rotary engine is driven in the state of the engine separated from a vehicle body.

This performance measuring device comprises a voltmeter part 14 displaying an output voltage from a position sensor detecting the position of a control pin, a step number display part 16 displaying the number of steps of step signals controlling a stepping motor, a computer connection terminal 18 for connecting to an engine control computer for a car on which the rotary engine is mounted, and a motor connection terminal 20 for feeding the step signals to the stepping motor.