To provide an infrared irradiation lamp for a vehicle which does not make long unevenness of light in the front-back direction on the road due to light unevenness of a filament image of a light source bulb to reduce incorrect detection of white lines due to the light unevenness.

The infrared irradiation lamp for the vehicle 100 comprises a convex lens 33 placed on an optical axis Ax extending along the front-back direction of the vehicle, a light source bulb 27 which is placed on the back side of the convex lens 33 and has a light emitting filament 27a, a reflector 29 which reflects light from the light source bulb 27 to the front toward the optical axis Ax, an infrared transmitting film 35a placed between the reflector and the projection lens 33. The light source bulb 27 is placed so that the longer direction of the filament 27a can intersect the optical axis Ax in an approximately perpendicular manner.