A retractor and a seat belt device that can achieve miniaturization of a device by thinning a part of an automatic lock mechanism. The automatic lock mechanism includes a switching plate that is rotatably connected to the spool via a speed reduction gear, and a lever member that is operated by the switching plate. The switching plate includes a disc-shaped guide part, a first projected part disposed on a first surface of the guide part, and a second projected part disposed on a second surface of the guide part. The lever member includes a first lever in contact with the first projected part, a second lever in contact with the second projected part, and a gap disposed between the first lever and the second lever, through which the guide part can pass.