A radiation imaging apparatus is provided. The apparatus includes an imaging unit including pixels and a control unit. Each of the pixels includes a conversion unit and a sample/hold circuit. The control unit causes the imaging unit to perform first imaging and second imaging after the first imaging to generate one energy subtraction image, and controls a timing of causing the sample/hold circuit in the first imaging to sample a first image signal obtained by the first imaging and a timing of causing the sample/hold circuit in the second imaging to sample a second image signal obtained by the second imaging in accordance with radiation irradiation conditions set in advance so as to reduce a difference between an amount of noise contained in the first image signal and an amount of noise contained in the second image signal.