An irradiation dose calculator calculates a pre-exposure-mode-required irradiation dose using the thickness of a breast which measured by a thickness measuring unit, as a parameter, and the irradiation time of a pre-exposure mode is controlled to apply a radiation to the breast in the pre-exposure mode. According to the dose of the radiation detected by a dose detecting sensor in the pre-exposure mode, the irradiation dose calculator calculates a main-exposure-mode-required irradiation dose, and the irradiation time of a main exposure mode is controlled to apply the radiation to the breast in the main exposure mode, thereby capturing a radiation image of the breast.