A fluid machine (1a-1f) comprising: a multi-stage compressor that includes a first compressor having a first inlet and a first outlet , a second compressor having a second inlet and a second outlet , and a bearing supporting a shaft for driving at least one of the first compressor and the second compressor , the first compressor sucking a gas refrigerant through the first inlet , compressing the gas refrigerant, and discharging the gas refrigerant through the first outlet , the second compressor sucking the gas refrigerant discharged from the first outlet through the second inlet , compressing the gas refrigerant, and discharging the gas refrigerant through the second outlet ; a pressure container that stores a liquid lubricant whose main component is the same kind of substance as a main component of the refrigerant; a first supply path through which the liquid lubricant stored in the pressure container is supplied to the bearing , the first supply path connecting the pressure container with the bearing ; a pump that is disposed on the first supply path and pumps the liquid lubricant toward the bearing ; a first return path through which the liquid lubricant that has passed through the bearing is returned to the pressure container , the first return path connecting the bearing with the pressure container ; and an intermediate pressure space that is maintained at a pressure higher than a pressure of the gas refrigerant at the first inlet and lower than a pressure of the gas refrigerant at the second outlet during operation of the multi-stage compressor , wherein an internal space of the pressure container constitutes a part of the intermediate pressure space . a multi-stage compressor that includes a first compressor having a first inlet and a first outlet , a second compressor having a second inlet and a second outlet , and a bearing supporting a shaft for driving at least one of the first compressor and the second compressor , the first compressor sucking a gas refrigerant through the first inlet , compressing the gas refrigerant, and discharging the gas refrigerant through the first outlet , the second compressor sucking the gas refrigerant discharged from the first outlet through the second inlet , compressing the gas refrigerant, and discharging the gas refrigerant through the second outlet ; a pressure container that stores a liquid lubricant whose main component is the same kind of substance as a main component of the refrigerant; a first supply path through which the liquid lubricant stored in the pressure container is supplied to the bearing , the first supply path connecting the pressure container with the bearing ; a pump that is disposed on the first supply path and pumps the liquid lubricant toward the bearing ; a first return path through which the liquid lubricant that has passed through the bearing is returned to the pressure container , the first return path connecting the bearing with the pressure container ; and an intermediate pressure space that is maintained at a pressure higher than a pressure of the gas refrigerant at the first inlet and lower than a pressure of the gas refrigerant at the second outlet during operation of the multi-stage compressor , wherein an internal space of the pressure container constitutes a part of the intermediate pressure space . <EOS>