An electromagnetic actuator (20) includes: an electromagnetic coil (21); fixed portions (an inner yoke (22) and an outer yoke (23)) placed around the electromagnetic coil (21); and an armature (24) which forms a magnetic circuit M of the electromagnetic coil (21) together with the fixed portions and which operates a sleeve (12) by moving in an axial direction of an axis C due to an electromagnetic force generated in the magnetic circuit M. The armature (24) is constituted by two members, i.e., a first member (24a) and a second member (24b). The first member (24a) and the second member (24b) of the armature (24) are individually supported by the fixed portions, and incorporated to each other by sandwiching the sleeve (12) from both sides in a moving direction (the axial direction). Hereby, a thrust can be transmitted to the sleeve (12) appropriately.