PURPOSE: To prevent a bearing from seizing by making a control bearing lubricated by oil used for other bearings to include rotary shaft in radial direction, be equipped with a seizure detecting means and highly sensitive against lubrication condition degradation than other bearings do.

CONSTITUTION: A slide bearing of an internal combustion engine 1 is lubricated by oil circulation and the oil is injected again into the slide bearing of the engine 1 from an oil sump 6 of the engine via a cooler 7, pump 8, and filter 9. A bypass circuit comprising ducts 10, 11 is equipped on a normal lubrication circuit and connected to in between an oil entrance and oil exit of the engine 1 to enable the bypass circuit to be shut off from the normal circuit by valves 12, 13 at need. An auxiliary engine 14 drives a shaft 15 supported by a control bearing 16 which is lubricated by oil circulated in the bypass circuit and treated in the normal lubrication circuit. Since the control bearing is more sensitive against degradation of the lubrication condition than other bearings, it can preventively alarm the sudden generation of bearing seizure condition of the engine.