A vane pump includes a motor, a rotor rotated by the motor, a first casing having a pump chamber accommodating the rotor and a first flat part in a periphery of an opening of the pump chamber, a second casing having a second flat part joined to the first flat part to gas-tightly or liquid-tightly close the opening of the pump chamber, an elastic sheet disposed between the second casing and the motor, and a screw penetrating the first casing, the second casing and the elastic sheet. The screw is configured to fasten and join the first casing, the second casing and the elastic sheet to the motor.