An image input apparatus is provided which is capable of taking a still image with high quality and with easy operations. The image input apparatus disclosed herein has a video camera and an expansion board mounted on a personal computer. The video camera has a lens, a shutter release switch, an image pickup device, a VIDS circuit, and the like. The expansion board connected via a camera cable to the video camera has a VIDS circuit, an A/D converter, a synchronous signal generator, and the like. As the shutter release switch of the video camera is depressed, the expansion board is controlled to read still image data and compress it. As the shutter release switch is released, it is controlled to resume the initial operations of reading moving image data and compressing it.