An illumination lens consists of two lenses consisting of a first lens and a second lens arranged in this order from a light source side, and surfaces of all the lenses have a planar shape or a convexly spherical shape. An incident surface of the first lens is a convex surface, and an emission surface of the second lens is a flat surface. An intersection of a ray incident in parallel to an optical axis at a height of 0.25×H and a ray incident in parallel to the optical axis at a height of 0.5×H is positioned only inside the illumination lens in a case in which an outer diameter of the first lens is denoted by 2H. Predetermined Conditional Expression related to a focal length of the illumination lens and a focal length of the first lens is satisfied.
