1. A movement amount estimation device, comprising: at least one processor; and at least one memory which stores a plurality of instructions, which when executed by the at least one processor, cause the at least one processor to execute: generating a first edge removed image by removing a first removal target edge based on a change in brightness indicated by edge intensity in one direction from an inner side to an outer side of a mobile body from a first edge image, the first edge image being generated from a first image taken by an imaging device mounted on the mobile body; generating a second edge-removed image by removing a second removal target edge based on the change in brightness indicated by the edge intensity in the direction from the inner side to the outer side of the mobile body from a second edge image, the second edge image being generated from a second image taken at a different clock time than the first image; and outputting a movement amount of the mobile body that is estimated based on the first edge-removed image and the second edge-removed image.