A portable terminal device includes: an operation part 7 including operation keys 71 that are two-dimensionally arranged in a matrix form; an image enlarging part 91 that, in a state where a plurality of enlargement target areas 93 are preliminarily set as partial areas of an image, generates an enlarged image by, on the basis of an operation of any of the operation keys 71, enlarging an image within an enlargement target area 93 preliminarily related to the operation key 71; a display image generating part 92 that generates a display image including the image in a normal or an enlargement browsing mode generates a display image including the enlarged image; and a display part 5 that displays the display image. The respective enlargement target areas 93 respectively correspond in an arrangement order to the operation keys 71, and form overlap areas with their adjacent enlargement target areas.