OPTICAL MODULE

An optical module according to one embodiment includes: a beam splitter having a first surface, a second surface facing the first surface, a third surface intersecting with the first surface, a fourth surface facing the third surface, and an inner surface formed within a region defined by the first surface, the second surface, the third surface, and the fourth surface; and a light receiving unit arranged at a position facing the third surface of the beam splitter. The beam splitter splits first incident light incident from the first surface into first split light transmitted through the inner surface and emitted from the second surface and second split light reflected on the inner surface and emitted from the third surface. The optical module includes a light absorbing/reflecting unit provided on the fourth surface.