A periphery monitoring apparatus comprising: an image capturing unit configured to generate a captured image by capturing a periphery of a mobile body; and a controller configured to generate, from the captured image, a peripheral image representing a view from a virtual viewpoint that is set at a relative position to a current position of the mobile body depending on a movement of the mobile body, generate a display image in which a mobile body image representing a position of the mobile body is superimposed on the peripheral image, and display the display image on a display device, and update the display image according to a moving distance of the mobile body, characterized in that the controller is configured to carry out the generation of the peripheral image by projecting a past captured image onto a preset virtual projection plane, wherein the past captured image has been captured by the image capturing unit in the past at an imaged position that is different from the current position, carry out the update of the display image by generating a new peripheral image based on a new current position of the mobile body, and generating an updated display image by superimposing the mobile body image of the display image onto the new peripheral image without changing a position of the mobile body image within a screen of the display device. an image capturing unit configured to generate a captured image by capturing a periphery of a mobile body; and a controller configured to generate, from the captured image, a peripheral image representing a view from a virtual viewpoint that is set at a relative position to a current position of the mobile body depending on a movement of the mobile body, generate a display image in which a mobile body image representing a position of the mobile body is superimposed on the peripheral image, and display the display image on a display device, and generate, from the captured image, a peripheral image representing a view from a virtual viewpoint that is set at a relative position to a current position of the mobile body depending on a movement of the mobile body, generate a display image in which a mobile body image representing a position of the mobile body is superimposed on the peripheral image, and display the display image on a display device, and update the display image according to a moving distance of the mobile body, characterized in that the controller is configured to carry out the generation of the peripheral image by projecting a past captured image onto a preset virtual projection plane, wherein the past captured image has been captured by the image capturing unit in the past at an imaged position that is different from the current position, carry out the update of the display image by generating a new peripheral image based on a new current position of the mobile body, and generating an updated display image by superimposing the mobile body image of the display image onto the new peripheral image without changing a position of the mobile body image within a screen of the display device. generating a new peripheral image based on a new current position of the mobile body, and generating an updated display image by superimposing the mobile body image of the display image onto the new peripheral image without changing a position of the mobile body image within a screen of the display device.