The present invention relates to a compact imaging apparatus. A memory in which one-line data is temporarily stored is provided between an analog processing system and a digital processing system. The analog processing system performs a series of processing from obtaining a pixel signal with an image pickup element to conversion of the pixel signal into digital data, and the digital processing system performs signal processing of the digital data into predetermined imaging data. A controller exclusively controls a one-line analog system operation performed by the analog processing system and a one-line digital system operation performed by the digital processing system. The controller operates the analog processing system with a maximum-speed clock which is possessed by the analog processing system, and the controller operates the digital processing system with a clock corresponding to a frequency determined by a bandwidth of a transmission system which transmits the imaging data. The controller turns on power source supply necessary for the operation of the analog processing system in performing the analog system operation f1 of the analog processing system, and the controller turns off the power source supply necessary for the operation of the analog processing system in performing the digital operation f2 of the digital processing system.