To reduce deterioration in the S/N of an output signal in correlative double sampling processing due to variance in delay among output signals of elements in difference line sensors and in one line sensor of a radiation image reader which photoelectrically converts stimulable light emitted by a stimulable phosphor sheet by a detecting means constituted by arraying line sensors in a horizontal scanning direction and performs the correlative double sampling processing for the photoelectrically converted signal to make a read.

A sampling control means 32 divides line sensors into two areas 23 and 24, determines the timing of the correlative double sampling processing by the areas, and controls a sampling means 31 according to the determined timing so that proper correlative double sampling processing is performed by the areas.