A super resolution image generating device capable of processing an image flexibly includes a scaling-up circuit, a front-end circuit, a first branch circuit, a second branch circuit, and an arithmetic circuit. The scaling-up circuit scales up the image to generate an enlarged image including N pixel values. The front-end circuit extracts features of the image to generate a front-end feature map. The first branch circuit extracts features of the front-end feature map to generate a first feature map, and scales up the first feature map to generate N first values. The second branch circuit processes the front-end feature map to generate a second feature map, scales up the second feature map to generate N second values, and processes the N second values to generate N processed values. The arithmetic circuit combines the N pixel values, the N first values, and the N processed values to generate a super resolution image.