To reduce the loss of available service life of a light source by turning on a light source of an original reader, when the depression of a key except a copy start key exists before the depression of the copy start key and turning off the light source, when the copy start key is not depressed down within a prescribed time after the depression of a key except the copy start key.

A reader controller 106 starts an optical reader with the depression of a key except a copy start key, such as a copy output setting key as a turning point and starts lighting control of a fluorescent lamp that is the light source 103. A time DT3, which is the time from a lamp being turned on with desired stable luminous intensity until image reading becomes available is the remaining time which is obtained by subtracting a time Tk that is taken from the depression of the key except the copy start key until the depression of the copy start key from a time T4 which is required to turn on the lamp, that is DT3=T4-Tk. There, when Tk>T4 and the difference between the time Tk and the time T4 becomes longer than the prescribed time, the lamp is turned off once to prevent the deterioration of the lamp.