A line sensor includes a light source section for irradiating light of a plurality of colors to an inspecting object, and a light-receiving section for detecting reflected light from the inspecting object. The light source section has a plurality of light sources for each of the plurality of colors. The light-receiving section has a plurality of light-receiving sensors disposed in a row. The light sources are disposed in two rows so that the light-receiving section is interposed between the two rows. The light sources of the plurality of colors are divided into a first color light source group and a second color light source group. First disposition patterns, in which the light sources of the first color light source group are disposed in one of the two rows and the light sources of the second color light source group are disposed in the other row, and second disposition patterns, in which the first and second color light source groups are disposed in positions opposite to the first disposition pattern, are alternately disposed.