PROBLEM TO BE SOLVED: To obtain an image signal processing circuit for a multiple screen display which is capable of preventing an outrunning phenomenon without a complicated prediction/judgment process, by detecting the state or phase of input-side field identification signals and output-side field identification signals when the reduction image data are generated for a multiple screen display. SOLUTION: An input filter unit 110 generates from the inputted field data the reduction image data for the divided screen display of odd-numbered and even-numbered fields through a process of carrying out reduction interpolation in a horizontal and a vertical direction in accordance with a coefficient from an input filter coefficient output unit 120. A selection unit 140 successively and circularly stores the generated reduction image data for a divided screen display of the odd-numbered and even-numbered fields in frame storages 140 and 150. A control unit 170 discriminates a frame storage to which writing access is not permitted and controls a selection unit 160 so as to read out the reduction image data for a divided screen display from the frame storage. COPYRIGHT: (C)2007,JPO&INPIT