A cylinder head cover integrated with an active oil mist separator may include a cylinder head cover body, a booster, and an oil mist separator. The cylinder head cover body may be provided with an exhaust passage and a separation passage. The booster may be mounted outside the cylinder head cover body. The booster may have a booster intake port and a booster exhaust port. The booster intake port may be connected with the exhaust passage. The booster exhaust port may be connected with the separation passage. The oil mist separator may be mounted in the separation passage and the oil mist separator may be located on a downstream side of the booster.