To provide maximum braking force in all engine speed ranges by optimizing the lift amount of an exhaust valve.

In an engine brake device for lifting an exhaust valve by pressing a release piston 3 by supply of oil pressure to an oil pressure chamber 19, an oil pressure supplying means for supping oil pressure corresponding to the engine speed to the piston 3, and energizing means 14a, 14b for energizing the release piston 3 to the oil pressure chamber 19 side and for lifting the release piston 3 by only the amount corresponding to the oil pressure value are provided.