A radiation imaging apparatus includes a unit constituted by arranging blocks in line and an information processing unit. Each of the blocks includes a conversion element configured to generate an image signal corresponding to radiation, a switching element connected between the conversion element and a column signal line, a detection element configured to detect radiation, and a detection signal line connected to the detection element. The information processing unit corrects a signal from the detection element, by using a value of the signal based on a parasitic capacitance between the conversion elements arranged on the same column as a column of the detection element.