Provided is an optical measurement device configured so that a high-accuracy three-dimensional image can be obtained. An emission angle of a ray of light is changed in such a manner that the rotation frequencies of two motors configured to rotatably drive a first optical path changing unit and a second optical path changing unit is controlled. The ray of light is emitted to a front three-dimensional region, and reflected light is obtained. Then, calculation is made by a computer, and in this manner, three-dimensional data on a measurement target object is obtained. The amount (vibration amount) of axial backlash or play of a rotary mechanism, such as a motor shaft, along which the ray of light is emitted is measured in real time, and such a backlash or play amount is subtracted from a three-dimensional image obtained by the computer. Consequently, a high-accuracy three-dimensional image is obtained.