Abstract: A continuous method of press forming a sheet resin, which is capable of subjecting to a consecutive process the steps of extruding a molten resin, forming the molten resin into a sheet resin strip, cutting the sheet resin strip into sheet resin pieces and press forming the sheet resin pieces. These steps are continuously carried out synchronously with one another by means of synchronizing devices, while the sheet resin is maintained at the desired temperature so as to possess proper thermoplasticity and surface stiffness through the medium of two thermal controls.