Molded resin body production method

A method for producing a resin molded article using a molding machine provided with a hopper for resin, an extruder, and a pressure control device in this order, the method comprising:

• feeding the resin into the hopper;
• passing the resin fed from the hopper through the molding machine to produce the resin molded article, and
• adjusting a resin pressure between a tip of the extruder and an inlet port for resin of the pressure control device to be 15.0 MPa or lower with the pressure control device, such that, through the adjustment of the resin pressure by the pressure control device a percent change between a melt flow rate of the resin fed into the hopper and a melt flow rate of the resin of the resin molded article obtained is 50% or lower,
• wherein the melt flow rates are measured under the same conditions, and
• the resin is a thermoplastic fluororesin.