A rotational shaft 22 receives input of torque that is output from an electric motor 19. A housing 23 rotatably supports the rotational shaft 22. A cylinder block 24 inside the housing 23 rotates with the rotational shaft 22. The pistons 25 are supported relative to the respective cylinder chambers 24a in the cylinder block 24 so as to be slidably displaceable. A swash plate 26 is provided so as to come into contact with ends of the pistons 25 and be rotatable around the rotational shaft 22 with the pistons 25, and be rotatable about a rotation centerline that is obliquely inclined relative to the rotational shaft 22. A case 27 inside the housing 23 is pivotably supported relative to the housing 23. A bearing portion 28 holds the swash plate 26 relative to the case 27 so as to be rotatable around the rotation centerline.