To provide an interpolating operation method and a picture reader which sufficiently utilize excellent characteristics of an area CCD sensor where read elements are arranged in a houndstooth check state at the time of reading a film image by the area CCD sensor.

Image signals of two or more nearby read elements are interpolated and assigned to rearrange image signals of read elements, which are outputted from an area image sensor where read elements are arranged in the houndstooth check state, into a square, and a light source part which emits read light, the area image sensor, an image forming optical system which forms the image of projection light bearing an image photographed on a film on the area image sensor, and at least one of a pixel shift means of the area image sensor and an interpolating operation part which performs interpolating operation of image signals outputted from respective read elements of the area image sensor to rearrange pixels are provided. Thus excellent characteristics of the area CCD sensor are sufficiently utilized.