The invention discloses a novel position encoder, which is composed of a rotating shaft, a bearing, a casing, a rotating disk, an optical system, a position detector, a signal processing circuit boardand a signal line. The rotating disk is driven to rotate through rotating the rotating shaft, the optical system rotates, a laser beam emitted by a laser emitter in the optical system passes througha convex lens and forms a spot, the spot is incident on the photosensitive surface of the position detector, and when the position detector detects the spot emitted by the laser emitter moves along with the rotating shaft, the output end generates corresponding photocurrent signals, and the signals are processed by the signal processing circuit board to obtain corresponding voltage signals, the signals are transmitted out through the signal line, and a user can receive the signals conveniently.