A control apparatus connected to a plurality of radiographic imaging apparatuses, includes a receiver that receives state information indicating whether a state is a first state in which the radiographic imaging apparatus is not connected to or synchronized with a specific synchronization source or a second state in which the radiographic imaging apparatus is connected to and synchronized with the specific synchronization source, from each of the plurality of radiographic imaging apparatuses, a hardware processor that makes a first determination that at least one of the plurality of radiographic imaging apparatuses is in the first state or a second determination that all of the plurality of radiographic imaging apparatuses are in the second state, based on the state information received from each of the plurality of radiographic imaging apparatuses, and an outputter that outputs whether a determination result by the hardware processor is the first determination or the second determination.