1. An endoscope device comprising: an insertion portion; an imaging element that generates an image based on a subject image formed through an optical system of the insertion portion; a monitor for displaying the image; an interface device that accepts input from a user; a memory having a measurement program stored thereon; and a processor that, under control of the measurement program stored in the memory, is configured to: obtain the image from the imaging element; display the obtained image on the monitor; set, on the displayed image, an edge extraction region; extract a plurality of edges from within an area of the edge extraction region set on the displayed image; display a first graphic indicating the plurality of extracted edges such that the first graphic is superimposed on the displayed image; after extracting the plurality of edges, set, according to an input from the interface device, a reference point on the displayed image on which the first graphic is superimposed; set, on the displayed image, a region based on the reference point as an edge selection region, the edge selection region being set to be smaller than the edge extraction region; identify edges that are included within the edge selection region, from among the plurality of extracted edges; select, according to an input from the interface device, one edge from among the edges identified as being included within the edge selection region as a reference line; display a second graphic indicating the selected reference line such that the second graphic is superimposed on the displayed image; set, according to an input from the interface device, a measurement point in the displayed image; calculate a spatial distance between the measurement point and the reference line; and display, on the monitor, a third graphic indicating a value of the spatial distance having been calculated.