In a sliding structure in which a shaft member is retained slidably in a guide hole, the lack of an oil film caused by the edge contact of the shaft member to which a pressing load in the axial direction is applied is prevented. With the fact being taken into account that end portions 25c1 and 25c2, which are always in slidable contact with a side surface 1232a of a guide hole 1232, of a side surface 25c of a shaft member 251 are the partial edge portion, a plurality of labyrinth grooves 2501 and 2502 are formed in the end portions 25c1 and 25c2, respectively, thereby it is possible for an oil film to cover the entire contact portion without increasing the groove width extremely. Because the groove width is not increased extremely, the length of the sliding portions can be ensured.