PURPOSE: To provide a position detecting element, by which a detected position signal can be directly obtained as a digital value.

CONSTITUTION: A position detecting element 1 comprises a photodetector element 3, which detects the position of spot light L, and an M-series-signal generating means 13, which generates the M-series signal by the movement of the incident spot light L on the light receiving surface of the position detecting element 1. In the M-series-signal generating means 13, a transparent electrode 5 (or a rear-surface electrode 7) comprising electrodes 5XA and 5XB (or 7YA and 7YB) formed with a dividing line 15 (or 19) as a boundary is provided. The dividing line 15 (or 19) imparts the dividing ratio to the photodetector element 3 corresponding to the codes of the M series. The transparent electrode 5 of the electrodes 5XA and 5XB formed with the dividing line 15, which gives the dividing ratio corresponding to the codes of the M series, as a boundary and the rear surface electrode 7 of the electrodes 7YA and 7YB having the similar structure are arranged in the orthogonally intersecting directions of the dividing lines 15 and 19 at the upper and rear surfaces of the photodetector element 3. Thus, the two-dimensional position detecting element can be obtained.