A quality control system for an irradiation apparatus includes a radiation image reading system. The radiation image reading system reads out a radiation image from a stimulable phosphor panel which is disposed in a predetermined position to receive irradiation of position check radiation from an irradiation system and irradiation of uniform radiation from the irradiation system to an area larger than the area exposed to the position check radiation and to receive irradiation of position check light in a visible region from a position check light irradiation system after receiving the irradiation of the uniform radiation and to form a radiation image. A relative position obtaining system obtains the relation between the irradiating position of the position check radiation and the irradiating position of the position check light on the basis of the radiation image read by the radiation image reading system.