The invention relates to a gas exchange valve mechanism (10) for an internal combustion engine (14), especially the internal combustion engine of a motor vehicle, which comprises a hydraulic device (15). Said hydraulic device comprises a fluid cycle (38, 42, 46, 54), a pressure accumulator (62, 72) which is connected to the fluid cycle (38, 42, 46, 54) and which has a piston (66, 76) prestressed by a mechanism (68, 84), and a controlled actuator (16). The inventive mechanism further comprises a gas exchange valve (12) whose valve element (26) is impinged upon by the actuator (16). The aim of the invention is to simplify the design of the gas exchange valve mechanism (10). To this end, the pressure accumulator (72) is mounted in such a manner that its piston (76), in a substantially pressureless state of the pressure accumulator (72), at least indirectly blocks the valve element (26) of the gas exchange valve (12) in a substantially closed position.