PURPOSE: To prevent seizure of revolving parts of a turbocharger, by enabling to feed oil to lubricating portions of the turbocarger after stopping of an engine, and thereby preventing oilless rotation of the revolving parts of the turbocharger after rapid stopping of the engine.

CONSTITUTION: When an ignition switch 36 is closed and an engine is kept in operation, oil is supplied from a main oil pump to lubricating portions of a turbocharger. Since, in this state, a normally opened contact 34 of an ignition relay 32 is closed, a normally closed contact 37 of a sensor relay 33 is opened. On the other hand, when the ignition switch 36 is opened and the engine is stopped, operation of the main oil pump is stopped. With opening of the ignition switch 36, the normally opened contact 34 of the ignition relay 32 is opened and an exciting coil 38 of the sensor relay 33 is de-energized, so that its normally closed contact 37 is closed. At the same time, a timer means 42 is set into operation, a normally opened contact 40 is closed and a motor 28 is set into operation. Through the operation of the motor 28, a pump 23 is set into operation to supply oil to the lubricating portions of the turbocharger.