The device relates to a piston pump, in particular a high pressure pump for a fuel injection device of an internal combustion engine, with at least one piston that is supported so that the piston can slide in a piston guide provided in a housing. A drive shaft is supported in the housing (10) on which drive shaft a crank element is provided. A stroke ring is supported in rotary fashion on the crank element and the piston can be acted upon by the drive shaft by way of this stroke ring. In order to prevent high lateral forces on the piston, the piston is supported on the non-rotating stroke ring with a sliding surface disposed on it against an associated slide bearing surface, wherein lubrication grooves are let into the slide bearing surface, crosswise to the relative motion between the piston and the stroke ring.