An absolute position encoder outputs position data as absolute data. When a power supply is turned on, absolute position data is read from an absolute code pattern (6) and is set in a counter (14). Thereafter, the counter (14) effects counting of incremental pulses read from an incremental code pattern (7) and increments the contents of the counter (14). Accurate absolute data referenced upon startup to the absolute code pattern can thus be output even during a high speed rotation.