A radiation imaging apparatus comprises a radiation detection unit that detects radiation, an instruction unit that issues a radiation-imaging start instruction, and a setting unit to set an irradiation delay period that extends between the issuance of an imaging start instruction and the time irradiation begins. A first acquisition unit acquires a plurality of dark current images during the set irradiation delay period, and a second acquires a radiation image of the object after the end of the set irradiation delay period. A correction data generation unit generate correction data for the acquired radiation image, based on the dark current images, and a correction unit executes dark current correction processing of the acquired radiation image using the correction data.