PURPOSE: To prevent a decrease in output and disorder of a waveform due to an axis shift by arranging magnetized patterns on a magnetic drum in the decreasing order of recording density from a driving source side.

CONSTITUTION: The magnetized patterns are arranged on the magnetic drum of a magnetic pulse encoder in the order of an increment phase 21, absolute phase 23, and Z phase 22 from the driving source side M. Consequently, the decrease in output and disorder of waveform due to the axis shift are prevented, and the permissible value of the positioning of a magneto-resistance effect element is increased to facilitate the positioning.