1. A head-mounted display device with which a user can visually recognize a virtual image and an outside scene simultaneously, the head-mounted display device comprising: a first image pickup unit configured to acquire a first outside scene image, the first image pickup unit being arranged in a position between a right eye and a left eye of the user; a second image pickup unit configured to acquire a second outside scene image and arranged in a position corresponding to the right eye or a right temple of the user or a periphery of the right eye or the right temple during wearing of the head-mounted display device by the user; a third image pickup unit configured to acquire a third outside scene image and arranged in a position corresponding to the left eye or a left temple of the user or a periphery of the left eye or the left temple during wearing of the head-mounted display device by the user; an augmented-reality processing unit configured to analyze the acquired first, second, and third outside scene images and generate additional image data for augmented reality according to a result of the analysis; a display element configured to generate image light using the generated additional image data; a light guide unit configured to form a virtual image before the eyes of the user using the generated image light; and a storing unit having stored therein guide image data for showing a display region for the virtual image to the user, the guide image data having a rectangular shape and including a plurality of guide marks arranged in each of a plurality of corners of the guide image data, wherein the augmented-reality processing unit acquires an overlapping region where the display region for the virtual image and an image pickup region of the first image pickup unit overlap in the first outside scene image and generates the additional image data using the overlapping region, in acquiring the overlapping region, the augmented-reality processing unit causes the display element to generate image light using the guide image data, guides the user to indicate positions of each of the plurality of guide marks in a given sequence, causes the first image pickup unit to acquire the first outside scene image, and acquires, as a boundary between the overlapping region and other regions, the positions indicated by the user obtained by analyzing the acquired first outside scene image, the augmented-reality processing unit generates the additional image data for augmented reality display in both the overlapping region and a region outside of the overlapping region based on the analysis of the first, second, and third outside scene images, the additional image data generated for display in the overlapping region by the display element is displayed to be recognized by a user of the head-mounted display device, and the additional image data generated for the region outside of the overlapping region is indicated to be present outside the overlapping region by displaying an icon indicating presence of the additional image data outside of the overlapping region.