An illumination lens consists of a first lens and a second lens that are arranged in this order from a light source side toward an irradiation target side. The surface of the first lens close to the light source side and the surface of the first lens close to the irradiation target side are spherical convex surfaces, and the surface of the second lens close to the light source side is a spherical convex surface. Conditional expression determined in advance about the radii of curvature of the surfaces of the first and second lenses is satisfied.
