An optical axis inspection apparatus is provided with: a camera for capturing a light distribution pattern of a light source device projected on a screen; an image processing device for finding a cutoff line in the light distribution pattern; an acceptance reference cutoff line setting unit; and a shade having an oblong slit and arranged to be opposed to a projection lens of the projection type light source device. Whether or not an optical axis is proper is inspected based oh a shift of the cutoff line with respect to the acceptance reference cutoff line. Only a transmissive light passing through a substantially central portion in a vertical direction of a projection lens including an optical axis of the projection lens is guided onto the screen by the shade.