To provide a digital image pickup device in which an arithmetic time can be shortened, and the next photographing can be quickly prepared by converting picture data into YUV data and thinning-out UV data at the time of operating distortion correction by an arithmetic operation by using an inexpensive lens with relatively large distortion.

The coefficient of an approximate polynomial indicating image height versus distortion curve being the lens performance characteristics of a photographing lens 1 is stored in an ROM 7. The RGB data of a subject fetched from the photographing lens 1 are temporarily stored in a buffer memory 5. The RGB data stored in the buffer memory 5 are converted into YUV data, and UV data are thinned out by a YUV data converting and thinning-out part 6a. In this case, the arithmetic operation of the approximate polynomial is executed by using the coefficient stored in the ROM 7 and the coordinate data of each picture element of the YUV data as the result of thinning-out by an approximate polynomial operating part 6b. Then, an interpolation operation is executed by an interpolation operating part 6c.