PURPOSE: To manufacture an electromagnetic wave shielding molded product which is superior in electromagnetic wave shielding properties up to an end wall even if a molding device to manufacture a skin layer is not provided separately.

CONSTITUTION: A cavity 3 controlling the outside of an electromagnetic wave shielding hollow molded product 11 by clamping one mold l1 and the other mold 2 and a resin relief part 4 communicating with the cavity 3 through a communicating path 5 are formed and outer layer resin 8 is injected into the cavity 3 through an injection nozzle 6. Then the electromagnetic wave shielding hollow molded product 11 into which an inner layer 9a is interposed is manufactured so as to cross an end wall 11b by extruding in order the outer layer resin 8 and inner layer resin 9 to the resin relief part 4, by a method wherein a pressurizing fluid is pressed into the inner layer resin 9 while injecting or after injection of the inner layer resin 9 within the outer layer resin 8, a small hollow part 10 is formed and in succession the small hollow part 10 is expanded away by pressing the pressurizing fluid into the small hollow part 10.