A mobile electronic device includes a detector unit configured to detect a position and an orientation of the mobile electronic device and a control unit. The control unit monitors the orientation of the mobile electronic device for a predetermined period when the control unit detects a change of the orientation of the mobile electronic device from a former orientation. The control unit determines that a corner is detected when the mobile electronic device does not return to the former orientation within the predetermined period, and determines that the corner is not detected when the mobile electronic device returns to the former orientation within the predetermined period.