A small and inexpensive optical measurement apparatus is provided in which noise due to optical interference such as inter-layer crosstalk or speckle is suppressed. The optical measurement apparatus includes a light source to emit laser light, a high-frequency superimposing unit to superimpose a high-frequency current on a driving current to drive the light source, a light branching element to branch the laser light into signal light and reference light, an objective lens to condense and irradiate the signal light on a measurement object, a condensing position scanning unit to scan a condensing position of the signal light, a light path length adjusting unit to adjust a light path length difference between the signal light and the reference light, an interference optical system which combines the signal light reflected or scattered by the measurement object and the reference light, and generates a plurality of interference lights different from each other in phase relation, and a photodetector to detect the interference lights.