Vehicle door structure having plastic door panel

A vehicle door structure including an inner door panel made of a plastic material, an outer door panel made of a plastic material and connected at peripheral portions with said inner door panel to form a door panel structure having front, rear and lower edge portions wherein said inner and outer door panels are connected together, reinforcement frame means provided in said door panel structure and including a front member extending substantially along said front edge portion of said door panel structure and a rear member extending substantially along said rear edge portion of said door panel structure and connected with said front member through a longitudinally extending member, characterized by the fact said front member of the reinforcement frame means is of a substantially U-shaped cross-section having an outer and inner flanges and a front wall between said outer and inner flanges, said longitudinally extending member having a front end portion connected with said front member at a portion other than the inner flange, connecting gusset means being provided for connecting said front end portion of the longitudinally extending member with said inner flange of said front member of the reinforcement frame means.