An illuminating lens (1) includes a light entrance surface (11), a light exit surface (12), and a bottom surface (13). The light entrance surface (11) has a first light entrance surface (111) and a second light entrance surface (112). The first light entrance surface (111) is a curved surface convex toward the light exit surface (12) and perpendicularly intersecting an optical axis A, and the second light entrance surface (112) extends outwardly from an edge of the first light entrance surface (111) and is connected obliquely to an inner edge of the bottom surface (13). In a cross section in a light spreading direction, θ1 has a negative value at the first light entrance surface (111) and a positive value at the second light entrance surface (112), where θ1 is a refraction angle at which virtual light reaching the light entrance surface (11) directly from a starting point Q on the optical axis A corresponding to a position of a light source (20) passes through the light entrance surface (11), and θ1 is defined as negative when θ1 is on the side of the optical axis A with respect to a normal N to the light entrance surface (11) and as positive when θ1 is on the opposite side.