A vehicle lamp can include a light source unit including a light guide plate with a light emission surface, and a point or line light source opposed to one end face of the light guide plate. The light guide plate can be made of a transparent plate-like material. A convex projection lens can be configured to focus light emitted from the light source unit and project the light forward in a direction of light illumination. The light guide plate can have a prism array on a rear surface thereof extending with a serrated cross section from the one end face to the opposite end face of the light guide plate, and in a direction parallel with the end face. The prism array can include a plurality of prism surfaces, with each prism surface being obliquely formed so that when light enters the light guide plate from the light source side and impinges thereon, a substantial amount of the light can be totally reflected into small angles of incidence to the emission surface. The projection lens can be disposed such that a focus thereof on a light source unit side is located on the light emission surface of the light guide plate.