An imaging apparatus comprising: a pixel array unit provided with a predetermined number of pixel blocks, wherein each pixel block comprises one floating diffusion layer, a plurality of transfer transistors (231, 232, 235, 236, 242, 243, 247, 248) and a plurality of photoelectric conversion devices (233, 234, 237, 238, 245, 246, 249, 250), wherein each of the transfer transistors is connected to a respective photoelectric conversion device and wherein the plurality of transfer transistors (231, 232, 235, 236, 242, 243, 247, 248) is configured to transfer the charges from their respective photoelectric conversion devices (233, 234, 237, 238, 245, 246, 249, 250) to the floating diffusion layer; a scan circuit configured to, for each pixel block, control the plurality of transfer transistors (231, 232, 235, 236, 242, 243, 247, 248) in a pixel addition mode in which pixel addition is performed, to simultaneously transfer the charges to the floating diffusion layer, and to control the plurality of transfer transistors (231, 232, 235, 236, 242, 243, 247, 248) in a normal mode in which pixel addition is not performed, to sequentially transfer the charges to the floating diffusion layer; an analog-to-digital conversion unit configured to perform analog-to-digital conversion on an analog signal being either an addition signal or a pixel signal, wherein the input addition signal is an analog signal generated in the pixel addition mode, and output as addition data; and wherein the pixel array unit is configured to generate an image signal in the normal mode including the analog signal being a pixel signal; an event detection unit (125; 280) configured to detect presence or absence of a predetermined event on the basis of the addition data, and to generate a detection result; an exposure control unit (124; 270) configured to control an exposure amount of the pixel array unit on the basis of luminance integral data obtained by integrating the predetermined number of pieces of the addition data; and a mode control unit (126; 290) configured to set the normal mode from the pixel addition mode in a case where the detection result indicates that the predetermined event has occurred, and to set the pixel addition mode from the normal mode in a case where a certain number of image signals are generated a pixel array unit provided with a predetermined number of pixel blocks, wherein each pixel block comprises one floating diffusion layer, a plurality of transfer transistors (231, 232, 235, 236, 242, 243, 247, 248) and a plurality of photoelectric conversion devices (233, 234, 237, 238, 245, 246, 249, 250), wherein each of the transfer transistors is connected to a respective photoelectric conversion device and wherein the plurality of transfer transistors (231, 232, 235, 236, 242, 243, 247, 248) is configured to transfer the charges from their respective photoelectric conversion devices (233, 234, 237, 238, 245, 246, 249, 250) to the floating diffusion layer; a scan circuit configured to, for each pixel block, control the plurality of transfer transistors (231, 232, 235, 236, 242, 243, 247, 248) in a pixel addition mode in which pixel addition is performed, to simultaneously transfer the charges to the floating diffusion layer, and to control the plurality of transfer transistors (231, 232, 235, 236, 242, 243, 247, 248) in a normal mode in which pixel addition is not performed, to sequentially transfer the charges to the floating diffusion layer; an analog-to-digital conversion unit configured to perform analog-to-digital conversion on an analog signal being either an addition signal or a pixel signal, wherein the input addition signal is an analog signal generated in the pixel addition mode, and output as addition data; and wherein the pixel array unit is configured to generate an image signal in the normal mode including the analog signal being a pixel signal; an event detection unit (125; 280) configured to detect presence or absence of a predetermined event on the basis of the addition data, and to generate a detection result; an exposure control unit (124; 270) configured to control an exposure amount of the pixel array unit on the basis of luminance integral data obtained by integrating the predetermined number of pieces of the addition data; and a mode control unit (126; 290) configured to set the normal mode from the pixel addition mode in a case where the detection result indicates that the predetermined event has occurred, and to set the pixel addition mode from the normal mode in a case where a certain number of image signals are generated