To provide an improper paper feeding detection device for a sheet-fed press capable of detecting a condition of improper paper feeding of a fed-in sheet (the presence or absence of sheet, traveling timing, etc.) and functioning to grip the sheet at a fixed position securely and transfer it.

At least two sets of detection devices having different sensibility including the detection device in which a reflection type photoelectric sensor on one side is arranged above a feeder board for the sheet-fed press and the detection device in which a reflection type photoelectric sensor on the other side is arranged in a paper feeding board part to use them selectively by switching them. Preferably, a reflection plate is stored in a case to detect a condition of improper paper feeding due to difference in received quantity of light.