An optical measurement apparatus includes: a moving mirror that changes an optical path length of one of two beams generated by splitting light subject to measurement; a drive mechanism that causes the moving mirror to reciprocate a predetermined distance in linear motion; a measured light receiver that detects intensity of light generated by superimposing the two beams; and a computation processor that sets a plurality of measurement ranges within the predetermined distance and calculates a measurement value based on a change in the light intensity detected by the measured light receiver for each of the measurement ranges.