A component separator comprising: a hollow main body which includes a communication pipe formed at one end portion thereof to allow a flow of body fluids therethrough and a main body female screw part disposed at the other end portion; a plunger which is installed inside of the main body , and has a plunger screw part formed in a center of a plunger lower portion which is integrally formed with a plunger head ; and an operation member which is installed inside of the main body to move the plunger forward and backward so as to vary a main body space , wherein the operation member comprises: a hollow pressing tube which has a pressing male screw part formed on an outer surface thereof so as to be screwed with the main body female screw part and a pressing tube protrusion formed at an end portion thereof on the plunger side, wherein the plunger is moved forward by rotating the hollow pressing tube ; and a plunger coupling tube which is slidably inserted inside of the pressing tube , and has a tube screw which is formed at a tip thereof and which is screwed with the plunger screw part in a state in which an end portion thereof on the plunger side is engaged to the pressing tube protrusion , wherein the pressing tube protrusion is disposed at a front end of the pressing male screw part so as to contact with a bottom of the plunger lower portion , wherein thread directions of the main body female screw part and the pressing male screw part are opposite to thread directions of the plunger screw part and the tube screw . a hollow main body which includes a communication pipe formed at one end portion thereof to allow a flow of body fluids therethrough and a main body female screw part disposed at the other end portion; a plunger which is installed inside of the main body , and has a plunger screw part formed in a center of a plunger lower portion which is integrally formed with a plunger head ; and an operation member which is installed inside of the main body to move the plunger forward and backward so as to vary a main body space , wherein the operation member comprises: a hollow pressing tube which has a pressing male screw part formed on an outer surface thereof so as to be screwed with the main body female screw part and a pressing tube protrusion formed at an end portion thereof on the plunger side, wherein the plunger is moved forward by rotating the hollow pressing tube ; and a plunger coupling tube which is slidably inserted inside of the pressing tube , and has a tube screw which is formed at a tip thereof and which is screwed with the plunger screw part in a state in which an end portion thereof on the plunger side is engaged to the pressing tube protrusion , wherein the pressing tube protrusion is disposed at a front end of the pressing male screw part so as to contact with a bottom of the plunger lower portion , wherein thread directions of the main body female screw part and the pressing male screw part are opposite to thread directions of the plunger screw part and the tube screw . a hollow pressing tube which has a pressing male screw part formed on an outer surface thereof so as to be screwed with the main body female screw part and a pressing tube protrusion formed at an end portion thereof on the plunger side, wherein the plunger is moved forward by rotating the hollow pressing tube ; and a plunger coupling tube which is slidably inserted inside of the pressing tube , and has a tube screw which is formed at a tip thereof and which is screwed with the plunger screw part in a state in which an end portion thereof on the plunger side is engaged to the pressing tube protrusion , wherein the pressing tube protrusion is disposed at a front end of the pressing male screw part so as to contact with a bottom of the plunger lower portion , wherein thread directions of the main body female screw part and the pressing male screw part are opposite to thread directions of the plunger screw part and the tube screw . <EOS>