PURPOSE: To permit efficient pressing and solidification of waste material contg. waste plastic by feeding a waste material contg. waste plastic charged to an introducing vessel section successively and forcibly from behind to a pressing section while keeping the pressing section and a forming nozzle at hot state.

CONSTITUTION: An introducing vessel section 1, a conical pressing section 4, a forming nozzle 5, and a forcing means 6, and a heating means 11, etc. for a waste material are provided. The material contg. waste plastic charged to the introducing vessel 1 is fed forcibly to the pressing section 4 successively from behind while heating the pressing section 4 and the forming nozzle 5. Thus, the plastic at the surfacial layer of the waste material contacting the internal peripheral surface of the pressing section 4 is softened to become fluidic, and the waste material is pressed and forced into the forming nozzle. Said plastic at the surfacial part of the waste material is melted by heating in the nozzle and a covering layer of plastic including the waste material is formed, which is then extruded through the nozzle to the outside where it is solidifed. By this method, waste material contg. plastic is efficiently pressed and solidified to permit convenient disposition.