Abstract: According to the present invention, there is provided a flow tester for thermoplastic which uses an extrusion type plastometer including a vertically supported cylinder, a piston on which a weight is mounted at an upper portion thereof and which is inserted in the cylinder, a die mounted on a lower end of the cylinder, and a heater provided to surround the cylinder, characterized in that a sample of a thermoplastic is filled in the cylinder and is heated by the heater to melt, the molten sample is extruded from the die by the piston, a strand as an extruded material is cut, and a mass thereof is obtained, thereby testing a flow characteristic of the thermoplastic, characterized by including a strand bottle which has a cutting edge for cutting the strand and which catches the strand cut by the cutting edge, a strand bottle stocker for storing the strand bottle before and after use, a weight measuring unit for measuring a weight of the cut strand together with the strand bottle, a strand cutting unit for moving