An apparatuses for pumping fuel to an internal combustion engine has a feed pump, a pressure line leading from the feed pump to the internal combustion engine, a check valve, and a pressure sensor connected to the pressure line is operatively connected to the pressure line downstream of the feed pump and upstream of the check valve. The measurement signal of the pressure sensor is used as a controlled variable for regulating the feed pump and/or for a leak diagnosis in the pressure line and/or for a tank leak diagnosis. The apparatus according to the invention is simplified because only a single pressure sensor is provided for the pressure change in the pressure line and in the tank.