Centrifugal compressor having equalizing vent to prevent grease from being pushed out of a bearing

A centrifugal compressor, comprising:

• an impeller which is provided to a shaft;
• a wall portion having an opposed surface that is spaced apart from and opposed to a back surface of the impeller;
• an insertion hole, which is formed in the wall portion, and is configured to receive the shaft inserted into the insertion hole;
• a bearing, which is provided in the insertion hole or apart from the impeller with respect to the insertion hole, is configured to axially support the shaft, and having grease lubricant inside;
• an electric motor which is provided on a side opposite to the impeller over the wall portion;
• and
• an opposed hole, which is formed in the wall portion, and has one end opened in the opposed surface and another end opened at a position opposed to a stator of the electric motor on a side opposite to the impeller,
• wherein the opposed hole comprises one or a plurality of opposed holes, and a sum total of an opening area at the one end is larger than an area of a circumferential gap formed in the opposed surface between an inner circumferential surface of the insertion hole and the shaft or a rotary member rotated integrally with the shaft.