In a color image reading apparatus of the present invention, a first light output controller 23 controls, in full-color reading, a variable current regulating circuit 7 according to first reference data from a first storage device 25 in synchronism with a first lighting controller 21 for setting the light output of each light emitting diode to a first predetermined level. Further, a second light output controller 24 controls, in monochrome reading, the variable current regulating circuit 7 according to second reference data from a second storage device 26 for setting the light output of a green light emitting diode, which is turned on continuously by a second lighting controller 22, to a second predetermined level less than the first predetermined level.
