An image processing device (1000) includes a luminance variation detection unit (1), an angular variation detection unit (2), an image region detection unit (3), and an image processing unit (4). The luminance variation detection unit (1) detects a degree of variation of pixel value in a pixel reference region including a pixel of interest and pixels around the pixel of interest. The angular variation detection unit (2) acquires a contour direction where the pixel value is constant in the pixel reference region for each pixel and detects a degree of variation of the acquired contour direction. The image region detection unit (3) acquires an image region detection signal representing characteristics of the image region including the pixel of interest based on the degree of variation of the pixel value and the degree of variation of the contour direction. The image processing unit (4) performs a predetermined image process on the pixel of interest based on the image region detection signal.