A compressor comprising: a cylindrical casing; a bundle which includes a tubular stationary member and a rotor accommodated into the stationary member, and which is inserted into an inner portion of the casing; and a roller configured to roll on an inner circumferential surface of the casing while supporting the bundle when the bundle is inserted into the inner portion of the casing along an axial direction, characterised in that an outer circumferential surface of the roller includes a center curved surface portion (23a, 412a) having a first curvature radius and an end side curved surface portion (23b, 23b1, 23b2, 412b) having a second curvature radius, the end side curved surface portion (23b, 23b1, 23b2, 412b) being arranged at both ends of the center curved surface portion (23a, 412a), and the center curved surface portion (23a, 412a) and the end side curved surface portion (23b, 23b1, 23b2, 412b) are formed in a continuous convex curved surface, in a state where at least the outer circumferential surface (23, 412) of the roller abuts the inner circumferential surface of the casing, the first curvature radius is the same as a curvature radius of the inner circumferential surface of the casing and is larger than the second curvature radius, the roller is disposed at a position which is deviated from a lower end in a vertical direction in the inner circumferential surface of the casing to a circumferential direction of the inner circumferential surface, and a curvature radius of the end side curved surface portion (23b, 23b1, 23b2, 412b) positioned at the vertically lower side is smaller than a curvature radius of the end side curved surface portion (23b, 23b1, 23b2, 412b) positioned at the upper side. a cylindrical casing; a bundle which includes a tubular stationary member and a rotor accommodated into the stationary member, and which is inserted into an inner portion of the casing; and a roller configured to roll on an inner circumferential surface of the casing while supporting the bundle when the bundle is inserted into the inner portion of the casing along an axial direction, characterised in that an outer circumferential surface of the roller includes a center curved surface portion (23a, 412a) having a first curvature radius and an end side curved surface portion (23b, 23b1, 23b2, 412b) having a second curvature radius, the end side curved surface portion (23b, 23b1, 23b2, 412b) being arranged at both ends of the center curved surface portion (23a, 412a), and the center curved surface portion (23a, 412a) and the end side curved surface portion (23b, 23b1, 23b2, 412b) are formed in a continuous convex curved surface, in a state where at least the outer circumferential surface (23, 412) of the roller abuts the inner circumferential surface of the casing, the first curvature radius is the same as a curvature radius of the inner circumferential surface of the casing and is larger than the second curvature radius, the roller is disposed at a position which is deviated from a lower end in a vertical direction in the inner circumferential surface of the casing to a circumferential direction of the inner circumferential surface, and a curvature radius of the end side curved surface portion (23b, 23b1, 23b2, 412b) positioned at the vertically lower side is smaller than a curvature radius of the end side curved surface portion (23b, 23b1, 23b2, 412b) positioned at the upper side.