An optical module includes: a mirror unit that includes a movable mirror and a fixed mirror, a beam splitter unit that constitutes an interference optical system in combination with the movable mirror and the fixed mirror; a light incident unit that causes measurement light to be incident to the beam splitter unit; a first light detector that detects interference light of the measurement light; a second light source that emits laser light; a second light detector that detects interference light of the laser light; a first mirror that has a function of allowing the measurement light to be transmitted therethrough and reflecting the laser light; a second mirror that has a function of reflecting a part of the laser light and allowing the remainder of the laser light to be transmitted therethrough; a third mirror that has a function of reflecting the laser light; and a first filter that has a function of allowing the measurement light to be transmitted therethrough and cutting off the laser light, and is disposed between the first mirror and the first light detector.