A piston pump for a high-pressure cleaning appliance is provided, which includes a plurality of pistons that are movable back and forth and each of which enters a pump chamber and is displaceably held at a piston guiding part. The piston guiding part has a supporting wall on which a plurality of guiding elements, each of which guides a piston, are disposed. In order to be able to produce the piston pump in a more cost-effective manner, it is proposed according to the invention that the supporting wall is curved.