A fluid machine includes a motor and a motor housing. The motor housing defines a motor chamber for accommodating the motor. The motor chamber is filled with inert gas. A rotor rotates in accordance with rotation of the motor. A pump housing defines a pump chamber for accommodating the rotor. A dividing wall is located between the pump housing and the motor housing. The pump housing and the motor housing are attached to each other via the dividing wall. Therefore, water is prevented from being generated in the motor chamber even if fluid that contains hydrogen leaks from the pump chamber to the motor chamber.