Abstract: There is disclosed an image processing circuit for displaying a plurality of sub-pictures which have different image signal sources on a common screen. The inventive subject digitalizes an original image analog signal by use of a corresponding sampled signal upon a multiple picture processing, saves the digitalized data almost simultaneously, and uses a dual-port memory for reading the data, whereby the circuit simplifies the generating process of a control timing signal and renders the PIP process easy to carry out, when controlling the dual-port memory by read-write operation. The apparatus for carrying out the invention includes a keyboard or remocon for data input/output, a microcomputer for controlling the entire process, a controller for controlling display processes, an analog switching device, an A/D converter for converting the analog signal to a digital signal, a dual-port memory for dealing with various image signals, and three D/A converters for converting digital data to analog data.