To prevent local abrasion of a vane spring by forming the shape of an opening part of a locking hole of a cylinder in a smooth round shape, or deforming the shape of an inclined part of the vane spring so as not to contact with an edge part of the locking hole of the cylinder.

A sealed motor-driven compressor has a compression element for always pressing a vane for sliding in a guide groove formed in a cylinder 9 by a vane spring 8 to compress fluid by the expansion/contraction of an actuating chamber partitioned by the vane to be delivered. In this case, a locking hole 9a having the prescribed depth and having an inside diameter slightly larger than a wire diameter of the vane spring 8 at an inclination almost equal to an inclination of an inclined part 8a of the vane spring 8, is formed on one side end surface of the cylinder 9. An opening part of this locking hole 9a is chamfered in a round shape to thereby smooth contact of the vane spring 8 with the locking hole 9a at compressor operating time to prevent local abrasion of the inclined part 8a.