A first imaging device and a second image device are connected with each other in a communicatable manner, and data of imaging timing and data of an exposure period of the first imaging device are transmitted to the second imaging device. In the second imaging device, the imaging timing and the exposure period can be set based on the data of the imaging timing and the data of the exposure period which are received. Therefore, an image is taken by the first imaging device and the second imaging device with the imaging timing and the exposure period of the first imaging device agreeing with those of the second imaging device.