NOVELTY - Device comprises a heating tank (100) for heating the crushed waste, a screw conveying unit for conveying by storing the heated waste, and an extrusion molding unit for producing solid fuel by compression molding the heated waste and discharging by cooling the obtained solid fuel. The device produces solid fuel by heating and extruding the combustible waste. The diameter or length of the crushed waste is less than or equal to 50% of the cross-sectional diameter of the solid fuel. The crushed waste is a mixed waste of 40-100% synthetic resin waste and 60-0% of crushed combustible waste.    USE - The device is useful for producing solid fuel (claimed).    ADVANTAGE - The device facilitates mass production of solid fuel, and improves strength and properties of solid fuel.    DETAILED DESCRIPTION - Device comprises a heating tank (100) for heating the crushed waste, a screw conveying unit for conveying by storing the heated waste, and an extrusion molding unit for producing solid fuel by compression molding the heated waste and discharging by cooling the obtained solid fuel. The device produces solid fuel by heating and extruding the combustible waste. The diameter or length of the crushed waste is less than or equal to 50% of the cross-sectional diameter of the solid fuel. The crushed waste is a mixed waste of 40-100% synthetic resin waste and 60-0% of crushed combustible waste. The heating tank heats and mixes the waste injected into a mixer (120). The heating tank comprises a waste heating unit for heating by contacting the injected waste with gas or air by injecting air into the heating tank or heated gas of high temperature from the outside; or heating by passing high temperature oil, air or heated gas through a heating tank body having jacket structure through installing an electrical heating unit outside the heating tank body. The mixer is double-walled and has an air jacket structure for supplying the heated air into the space of the body. The heating tank is provided with a substantially cylindrical body (110) for heating by contacting with waste with gas or air, and a driving unit (130) for rotating the mixer installed on one side of the body. The mixer comprises a rotating shaft rotating by a driving motor, and multiple mixing wings (122) radially formed at the outer peripheral surface of the rotating shaft. The mixing wings and the rotating shaft have a structure for circulating hot air or gas and are formed with an inlet port for introducing hot air into the free end portion of the multiple rotating shaft, and multiple discharge ports arranged in a row for flowing hot air from one side of the mixing wing. The screw conveying unit is provided with a waste inlet port for introducing waste by communicating with the inner space of the heating tank, and a waste outlet port for discharging the waste form the upper side of the extrusion molding unit. The waste inlet port is formed with an air inlet port for flowing hot air into the air Jacket by through the inner space of the heating tank, an air discharge port for circulating air introduced into the air Jacket and discharging air, and a screw unit longitudinally installed and equipped with a screw for rotating by the driving motor within the body. The compression molding unit comprises a cylinder placed at the upper side, and a discharging block formed with outlet port at the lower side and a pressing unit having an extruding plate for vertically moving the cylinder. The discharging block is connected to an extrusion molding block, a layered structure having a cooling block arranged on a cooling water jacket for cooling by introducing cooling water, and a solid fuel discharge port formed on the extrusion molding block and having a through hole of funnel shape. The heating unit, screw conveying unit and the extrusion molding unit prevent sticking of melted waste to the inner surface of the device by Teflon (RTM: Polytetrafluoroethylene) coating on the inside surface.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the device.    Heating tank (100)    Heating tank body (110)    Mixer (120)    Mixing wing (122)    Driving unit (130)