A reciprocating piston internal combustion engine having at least one camshaft with at least one sliding cam element with sliding cams and sliding grooves (2 and 2a) intersecting in an X-shape, wherein the sliding cam element with internal teeth (4) is mounted for conjoint rotation but axially movably on a toothed shaft (5), and wherein a guide element is fixed between the sliding grooves (2 and 2a), which guide element has elastically movable switch blades (10 and 10a) that are guided on a rotary joint plate (12) mounted in the intersection area. The engine further has an actuator device with at least one actuator pin (9) movable out of a housing, wherein the actuator device can be mounted on a component of a cylinder head or on the cylinder head of the reciprocating piston internal combustion engine, and, after having moved out, the actuator pin (9) comes into connection with at least one sliding groove (2 or 2a) of the sliding cam element, said guide element being constructed as a C-shaped spring (6) and fixed, at least at the ends thereof, on the toothed shaft (5).