A process and an apparatus for molding, in which a molten thermoplastic resin is firmly fitted onto a molding surface of a mold under a pressure lower than or equal to 100 kg/cm.sup.2 and is cured to obtain a molded product. The molding apparatus has a mold main body, and a mold body on which the molding surface is defined. The mold body is supported relative to the mold main body with maintaining a space on the back side of the molding surface in a heat insulative manner by a supporting member which includes at least a heat insulative supporting member having a thermal conductivity of 0.001 to 1 Kcal/mh.degree. C. and a longitudinal elastic modulus of 0.01 to 10 kg/cm.sup.2. In the space, a heating fluid for heating the molding surface from the back side to a temperature higher than or equal to Vicat softening temperature (T).degree. C. of the thermoplastic resin and a cooling fluid for cooling the molding surface from the back side to a temperature lower than or equal to (Vicat softening temperature (T) of the thermoplastic resin-10).degree. C. are supplied.