The purpose of the present invention is to enable the determination of whether to obtain a special-effect image to be controlled easily. A main body device 20 determines, based on information related to the optical axis directions of two imaging devices 10, whether the relative positional relationship of the respective imaging devices 10 is a predetermined positional relationship. When the relative positional relationship is the predetermined positional relationship, the main body device 20 targets, for synthesis processing, respective images captured by the respective imaging devices 10 in the positional relationship and sets the synthetic format, while when the relative positional relationship is not the predetermined positional relationship, the main body device 20 performs control to set the respective images captured by the respective imaging devices 10 in the positional relationship not to be synthesized without being targeted for the synthesis processing.