An HMD includes an image display section configured to display an image to enable visual recognition of an outside scene by transmitting external light, a mobile-body-position acquiring section configured to acquire a position of a mobile machine, an operation detecting section configured to detect operation, and a display control section configured to cause the image display section to display the image. The display control section executes visibility control processing for controlling, on the basis of the position of the mobile machine acquired by the mobile-body-position acquiring section and the operation detected by the operation detecting section, visibility of the image displayed by the image display section with respect to the external light transmitted through the image display section.