In a camera system wherein video signals generated by a plurality of cameras are transmitted in units of image frames to a host PC, in a shared isochronous band through an IEEE1394 bus, each of the cameras comprises an asynchronous streaming-packet receiving circuit configured to receive an asynchronous streaming packet transmitted to the IEEE1394 bus, an asynchronous streaming-packet transmitting circuit configured to transmit an asynchronous streaming packet to the IEEE1394 bus, and an image output switch configured to supply a video signal generated by any camera, in the form of an isochronous packet, to the IEEE1394 bus under the control of the asynchronous streaming-packet receiving circuit. The asynchronous streaming-packet receiving circuit causes the asynchronous streaming-packet transmitting circuit to transmit an acceptance packet, thereby enabling the image output switch to transmit the isochronous packet, upon receiving an asynchronous streaming packet which is addressed to the asynchronous streaming-packet receiving circuit and which assigns a right of using an isochronous band.