A double-scanning non-interlaced television receiver performs scanning line interpolation by using a memory to reproduce a 1/60 second frame with 525 scanning lines. The receiver has a picture-in-picture (P-in-P) function which inserts a frame (sub-picture) into a part of another frame (main picture). The receiver is provided with a signal processing circuit for implementing the scanning line interpolation and a memory having a frame-wide capacity for producing a sub-picture. The receiver (1) produces a video signal for the main scanning line and a video signal for the interpolated scanning line for the main picture and a video signal for the main scanning line and a video signal for the interpellated scanning line for the sub-picture and (2) performs a double-scanning conversion, thereby providing a sub-picture without causing line flicker.