Abstract: A fluid machine includes an electric motor, an inverter, a housing, a cover member that is fixed to the housing and defines an accommodation chamber, a sealing member that is disposed between the cover member and the housing, and a fastening member that is fastened to the housing. The housing has an insertion hole. The fastening member has a shank inserted into the insertion hole, a flange applying a fastening force to the cover member through a rubber washer, and a positioning portion defining positions of the shank and the flange relative to the housing. The cover member is supported on the housing. Stiffness of the rubber washer is greater than stiffness of the sealing member.