A light source module comprising: a light source having an upper surface comprising a light emission surface ; and a light-guide member comprising a lens portion having a rotation axis (C) that extends through the light emission surface , wherein the lens portion comprises: a concave incidence surface facing the light emission surface of the light source and configured to receive light from the light source ; a reflection surface disposed outside the incidence surface , the reflection surface being configured to reflect part of light entering through the incidence surface , and being inclined at an angle of 45 degrees or more from a direction perpendicular to the rotation axis (C); and an exit surface configured to allow part of the light entering through the incidence surface and light reflected by the reflection surface to exit the lens portion , and characterized in that the incidence surface comprises: a first incidence area having four-fold symmetry about the rotation axis (C) and having a curved concave shape in a first cross section containing the rotation axis (C); and a second incidence area having a curved convex shape in a second cross section rotated 45 degrees with respect to the first cross section around the rotation axis (C) and containing the rotation axis (C). a light source having an upper surface comprising a light emission surface ; and a light-guide member comprising a lens portion having a rotation axis (C) that extends through the light emission surface , wherein the lens portion comprises: a concave incidence surface facing the light emission surface of the light source and configured to receive light from the light source ; a reflection surface disposed outside the incidence surface , the reflection surface being configured to reflect part of light entering through the incidence surface , and being inclined at an angle of 45 degrees or more from a direction perpendicular to the rotation axis (C); and an exit surface configured to allow part of the light entering through the incidence surface and light reflected by the reflection surface to exit the lens portion , and characterized in that the incidence surface comprises: a first incidence area having four-fold symmetry about the rotation axis (C) and having a curved concave shape in a first cross section containing the rotation axis (C); and a second incidence area having a curved convex shape in a second cross section rotated 45 degrees with respect to the first cross section around the rotation axis (C) and containing the rotation axis (C). a concave incidence surface facing the light emission surface of the light source and configured to receive light from the light source ; a reflection surface disposed outside the incidence surface , the reflection surface being configured to reflect part of light entering through the incidence surface , and being inclined at an angle of 45 degrees or more from a direction perpendicular to the rotation axis (C); and an exit surface configured to allow part of the light entering through the incidence surface and light reflected by the reflection surface to exit the lens portion , and characterized in that the incidence surface comprises: a first incidence area having four-fold symmetry about the rotation axis (C) and having a curved concave shape in a first cross section containing the rotation axis (C); and a second incidence area having a curved convex shape in a second cross section rotated 45 degrees with respect to the first cross section around the rotation axis (C) and containing the rotation axis (C). a first incidence area having four-fold symmetry about the rotation axis (C) and having a curved concave shape in a first cross section containing the rotation axis (C); and a second incidence area having a curved convex shape in a second cross section rotated 45 degrees with respect to the first cross section around the rotation axis (C) and containing the rotation axis (C). <EOS>