PURPOSE: To reduce vibration of bearings by providing separated spacers between both the bearings on the turbine side and compressor side.

CONSTITUTION: When an engine is rotated, an oil pump is also driven and a part of lubricating oil for oiling the engine is led through the lubricating oil passage 3 of a bearing housing 1 to an oil film damper 2. Further, the lubricating oil is led from lubricating oil passages 3a, 3b provided to the oil film damper 2 through a lubricating oil passage 3c for spacer 6 on the turbine side, a spacer 7 on the compressor side to a ball bearing 4 on the turbine side and a ball bearing 5 on the compressor side. When thrust force acts on a turbine shaft 9 under the condition, separated spacers 6, 7 are pressed against the ball bearings 4, 5 by a spring 8 to prevent vibration in the thrust direction.