The present invention provides a recliner for vehicle seats. The recliner includes a gear rim, a guide plate, a lever rotating shaft, a cam, elastic members, a main control disk, locking gears and locking gear support members. The gear rim has internal gear teeth. The guide plate is coupled to the gear rim and has guide blocks thereon. The lever rotating shaft is inserted through the gear rim and the guide plate. The cam has support protrusions on both ends thereof. The elastic members are provided on the inner surface of the guide plate, and each elastic member elastically supports a first end of the corresponding support protrusion. The main control disk is coupled to the cam. Inner and outer guide holes are formed through the main control disk. The locking gears are slidably provided between the facing guide blocks, and each locking gear has a support depression. The support depression has a concave curved surface and a convex curved surface. External gear teeth are formed in each locking gear. Each locking gear support member has a first contact surface which is in close contact with the concave curved surface of the support depression, a second contact surface which is in close contact with the corresponding guide block, and an inner surface which is supported on both ends thereof by the cam.