PURPOSE: To output data from positional shift, by supporting the power source demand parts of a pulse generation means for detecting the moving operation of a moving body and a means for forming positional data by a power source backup circuit when a power source is cut off.

CONSTITUTION: A position detection apparatus 1 detects the position of a moving body with the rotation of a disc 13. The detected data is temporarily stored in a positional data memory part 23 and outputted to the outside through a terminal T1 on the basis the order of a transmission control circuit 29. In this position detection apparatus 1, a power source backup circuit 9 is provided and, when a power source is cut off, the power source backup of a power source demand part 33 is performed. Therefore, even when the power source is cut off, the positional data on the absolute coordinates of the moving body is always held and, if the power source is again closed, the positional data of the moving body can be transmitted through a serial communication control circuit 25 and the terminal T1.