An image pickup apparatus includes an image data production unit which produces data of images of a plurality of resolutions, from an image frame obtained by picking up an image of a target object as a moving picture for each pixel string which configures a row, and an image sending unit which extracts, from the data of the images of the plurality of resolutions, pixel strings of a region requested from a host terminal and connect the extracted pixel strings for each number of pixels determined in accordance with a given rule to produce a stream and then transmit the stream to the host terminal. The image sending unit adjusts a connection pixel number of data of an image of a particular resolution such that, where N is an integer, data for 1/(N+1) frame are transmitted with respect to one frame of data of an image of the other resolution.