An imaging apparatus to which an accessory is detachably attached includes an imaging unit configured to convert an object image into an electrical signal, a signal generation unit configured to generate a vertical synchronizing signal that is synchronized with a timing of exposure of the imaging unit and output the generated vertical synchronizing signal, a control unit configured to control communication with the accessory based on the vertical synchronizing signal, a first terminal configured to send a clock signal generated by the control unit to the accessory, and a second terminal configured to communicate data with the accessory based on the clock signal, in which the control unit controls a signal level at the first terminal to a predetermined level when the communication of the data ends, and then changes the signal level in synchronization with the output of the vertical synchronizing signal.