A split unit capable of providing a stereoscopic image having less laterality is provided. The split unit includes: a beam splitter which transmits first imaging light as a part of light incident on an incident surface of the beam splitter, and reflects second imaging light as another part of the light incident on the incident surface; and a reflecting member which reflects the second imaging light reflected by the beam splitter. At least one of a reflectance of the reflecting member and a beam splitting characteristic of the beam splitter is set based on the following formulae: T=d/(1+d) R=1−T where T (0≦T≦1) is a transmittance of the beam splitter, R (0≦R≦1) is a reflectance of the beam splitter, and d (0≦d≦1) is a reflectance of the reflecting member.