A refrigerant compressor including a sealed case, a compression mechanism contained in the sealed case, a motor part which is contained in the sealed case and drives the compression mechanism via a crank shaft, and an oil reservoir formed in a lower portion of the sealed case, the refrigerant compressor further comprising: an oil supply pipe which links an oil reservoir in the sealed case and a suction side of the compression mechanism by passage and introduces oil in the oil reservoir to the suction side; an oil supply amount adjusting means which is provided on the oil supply pipe and adjusts an amount of oil supply supplied to the suction side; a rotational speed detecting means which detects a rotational speed of the motor part; and an oil supply amount controlling unit which controls the oil supply amount adjusting means according to a rotational speed detected by the rotational speed detecting means, wherein the oil supply amount controlling unit controls the oil supply amount adjusting means in a manner that an amount of oil supply supplied to the suction side from the oil supply pipe decreases as a rotational speed of the motor part increases; characterized in that the refrigerant compressor further comprises: a discharge pressure detecting means which detects a pressure in a discharge side of the refrigerant compressor; and a suction pressure detecting means which detects a pressure in a suction side of the refrigerant compressor, wherein the oil supply amount controlling unit carries out control in a manner that an amount of oil supply supplied to the suction side from the oil supply pipe decreases as a rotational speed of the motor part increases, and controls the oil supply amount adjusting means so as to further decrease the amount of oil supply as a pressure difference between a discharge pressure detected by the discharge pressure detecting means and a suction pressure detected by the suction pressure detecting means increases. an oil supply pipe which links an oil reservoir in the sealed case and a suction side of the compression mechanism by passage and introduces oil in the oil reservoir to the suction side; an oil supply amount adjusting means which is provided on the oil supply pipe and adjusts an amount of oil supply supplied to the suction side; a rotational speed detecting means which detects a rotational speed of the motor part; and an oil supply amount controlling unit which controls the oil supply amount adjusting means according to a rotational speed detected by the rotational speed detecting means, wherein the oil supply amount controlling unit controls the oil supply amount adjusting means in a manner that an amount of oil supply supplied to the suction side from the oil supply pipe decreases as a rotational speed of the motor part increases; a discharge pressure detecting means which detects a pressure in a discharge side of the refrigerant compressor; and a suction pressure detecting means which detects a pressure in a suction side of the refrigerant compressor, wherein the oil supply amount controlling unit carries out control in a manner that an amount of oil supply supplied to the suction side from the oil supply pipe decreases as a rotational speed of the motor part increases, and controls the oil supply amount adjusting means so as to further decrease the amount of oil supply as a pressure difference between a discharge pressure detected by the discharge pressure detecting means and a suction pressure detected by the suction pressure detecting means increases.