The illumination apparatus includes a light source, an optical member configured to at least transmit therethrough light from the light source, and a reflective member configured to include a reflective portion which extends closer to the optical member than the light source and reflects the light from the light source to cause the light to enter the optical member. A concave portion is formed, on a light entrance side surface of the optical member, in an outside area located outside a light entrance area where the light reflected by the reflective portion reaches. The concave portion includes a refractive surface refracting light, which is part of the light from the light source and enters the concave portion without being reflected by the reflective portion, toward an exit surface of the optical member.