PURPOSE: To obtain a stable output signal by suitably maintaining an interval between a semiconductor laser as a light source and a collimator lens system.

CONSTITUTION: The optical type encoder comprises an optical scale 6 having a first scale for modulating lights from light emitting means 4, 5 and a second scale for remodulating the modulated light, photoreceiving means 7 for photoreceiving the light modulated by the second scale, an optical base 1 for fixedly placing the means 4, 5 and the means 7, and a buffer member 8 interposed between the base 1 and the means 4, 5.