An operation target device projects a display video onto a projection surface, which is captured by a camera. An operation detectable region specifying unit specifies respective regions where an operation is detectable and is undetectable in a range in which the display video is projected, based on image data captured by the camera. Finger and pen contact position detection units detect the operation to the operation object based on the image data. The operation target device displays the display video so that the region where the operation to the operation object is detectable, which is specified by the operation detectable region specifying unit, is distinguished from the region where the operation to the operation object is undetectable. The operation target device changes a display position of the operation object so the operation object is displayed within a range of the region where the operation to the operation object is detectable.