A sun visor includes a lock device (30) that is operable to lock a sun visor body (20) in a storage position adjacent to a vehicle cabin ceiling (1). The lock device (30) is operable to release the sun visor body (20) and to force the sun visor body (20) towards a light-shielding position by a predetermined angle when a locked sun visor body (20) is pressed towards the vehicle cabin ceiling (1). The lock device (30), including a cam ring (50), a spring engaging roller (80), a spring (90), and a lock member (70), may be axially movably fitted on a horizontal rod portion (12) of a support rod (10). The lock device (30) may be used for many types of sun visors, including sliding type sun visors and non-sliding type sun visors.