An oil-cooled type screw compressor having a compressor body that compresses a suction gas, and discharges the compressed gas, comprising: a rotor casing of the compressor body; a pair of male and female screw rotors that is stored in said rotor casing, and meshes with each other; rotor shafts that are provided for each of said screw rotors, and extend to both sides of each of said screw rotors respectively; a suction port that is provided for one side in a longitudinal direction of said screw rotors, and introduces the suction gas to said pair of screw rotors; a discharge port that is provided for the other side in the longitudinal direction of said screw rotors, and discharges the compressed gas compressed by said screw rotors; a disc-shaped thrust plate that is provided near either one of end portions, in the longitudinal direction, of each of said rotor shafts, and rotates integrally with said rotor shaft; a sealing member that seals said thrust plate rotatably while spacing it from said screw rotors, and that defines a first space and a second space on both sides of said thrust plate; a pair of thrust bearings that is disposed in the first space and the second space respectively, and receives a thrust force transmitted to said thrust plate placed between said thrust bearings; characterised in that an oil feed passage that communicates with such one of said first space and said second space that is located on the side to apply a force in a direction against the thrust force to said thrust plate when boosted, and that establishes the communication between an inside of said space and an oil feed source; an oil discharge passage that communicates with such one of said first space and said second space that is located on the side to apply a force in a direction against an anti-thrust force to said thrust plate when boosted, and that establishes the communication between an inside of said space and an oil discharge destination; and an oil distribution passage through which the oil is distributed between said first space and said second space. a rotor casing of the compressor body; a pair of male and female screw rotors that is stored in said rotor casing, and meshes with each other; rotor shafts that are provided for each of said screw rotors, and extend to both sides of each of said screw rotors respectively; a suction port that is provided for one side in a longitudinal direction of said screw rotors, and introduces the suction gas to said pair of screw rotors; a discharge port that is provided for the other side in the longitudinal direction of said screw rotors, and discharges the compressed gas compressed by said screw rotors; a disc-shaped thrust plate that is provided near either one of end portions, in the longitudinal direction, of each of said rotor shafts, and rotates integrally with said rotor shaft; a sealing member that seals said thrust plate rotatably while spacing it from said screw rotors, and that defines a first space and a second space on both sides of said thrust plate; a pair of thrust bearings that is disposed in the first space and the second space respectively, and receives a thrust force transmitted to said thrust plate placed between said thrust bearings; characterised in that an oil feed passage that communicates with such one of said first space and said second space that is located on the side to apply a force in a direction against the thrust force to said thrust plate when boosted, and that establishes the communication between an inside of said space and an oil feed source; an oil discharge passage that communicates with such one of said first space and said second space that is located on the side to apply a force in a direction against an anti-thrust force to said thrust plate when boosted, and that establishes the communication between an inside of said space and an oil discharge destination; and an oil distribution passage through which the oil is distributed between said first space and said second space.