To provide an image processing device capable of smoothly displaying, in I/P conversion, an image having an oblique line whose angle is close to horizontality or having edges of a protrusion.

An interpolation image generation unit 73 of the image processing device performs interpolation arithmetic using the pixel value and interpolation coefficient of each pixel adjacent in vertical direction of an interlaced image signal to calculate the pixel value of pixels on a line to be interpolated between adjacent horizontal lines of the interlaced image signal and generate a progressive image signal. When a row of consecutive horizontal pixels composed of pixels whose edge angle is almost horizontal and which are contiguous in the horizontal direction is an oblique line in the interlaced image signal, an interpolation coefficient calculation unit 72 causes an interpolation coefficient used by an interpolation image generation unit 73 to vary in a prescribed direction from one end of the row of consecutive horizontal pixels toward the other end thereof; when the row of consecutive horizontal pixels is a protrusion, the interpolation coefficient is varied in the prescribed direction from both ends of the row of consecutive horizontal pixels toward the center thereof.