To produce a molded product sufficiently uniform in wall thickness distribution from a thermoplastic resin plate by thermal molding.

In a method for producing a molded product by heating a thermoplastic resin plate to thermally mold the same, the dynamic elastic modulus (α) of the part (A) of the thermoplastic resin plate corresponding to the product center part of a molded product, the dynamic elastic modulus (β) of the part (B) of the thermoplastic resin plate corresponding to the part becoming the thinnest wall part in the molded product and the dynamic modulus (γ) of the part (C) of the thermoplastic resin plate corresponding to the outer peripheral part of the molded product satisfy a conditional formula: γ≤α... (I) and a conditional formula : α<β... (II) and the thermoplastic resin plate is heated so that a ratio (β/7γ) of γ and β becomes 1.4-5 to be thermally molded.