Image retrieval is facilitated. An image retrieval device is a device for retrieving an image with high similarity that is stored in a server computer by using a query image. In an image registration mode, a plurality of first images are supplied to a code generation portion, and the code generation portion resizes the number of pixels of the first image, converts the number of pixels of the first image into the number of pixels of a second image, and extracts a first feature value from the second image. The control portion links the first image to the first feature value corresponding to the first image and stores the first image and the first feature value in a storage portion. In an image selection mode, a first query image is supplied to the code generation portion, and the code generation portion resizes the number of pixels of the first query image, converts the number of pixels of the first query image into the number of pixels of a second query image, and extracts a third feature value from the second query image. The first image having the first feature value with high similarity with the second feature value is selected by an image selection portion, and the selected image is used as a query response.