An optical inner surface measurement device is provided; which includes a motor; a rotary optical fiber configured to be rotated by the motor; a fixed optical fiber configured not to rotate relative to the rotary optical fiber; and a runout detection sensor configured to measure a runout amount of the rotary optical fiber, wherein an optical path conversion device is arranged at a tip end of the rotary optical fiber, at a back of the motor, both end surfaces of the rotary optical fiber and the fixed optical fiber face each other with a minute clearance, and reflected light, which is captured by the optical path conversion device, from a measurement target object inner surface is guided to a measurement machine body by way of the rotary optical fiber and the fixed optical fiber and is analyzed by a computer to produce inner surface measurement data, and the inner surface measurement data is corrected based on the runout amount detected by the runout detection sensor.