An imaging apparatus for performing wireless communication with an external device. An instruction transmitting unit transmits an operation instruction to the external device. A response signal receiving unit receives a response signal from the external device. A first controlling unit starts a first operation relating to an imaging process in a case that a first time passes from a point of receiving the response signal by the response signal receiving unit. The external device executes a second operation relating to the imaging process in a case that a second time passes from a point of transmitting the response signal from the external device to the imaging apparatus.