A resin extrusion apparatus having a weighing device (11) connected to a controller (18). A powder container (12) for supplying a powder (Y) to a resin extruder (20), a screw (13), and a motor (14) are installed over the weighing device 11. The motor (14) rotates a powder feeder (10) in proportion to a frequency of an inverter (17) connected to the controller (18). The powder feeder (10) is installed on the resin extruder (20). The powder feeder (10) supplies the powder (Y) to the resin extruder (20) quantitatively by a feedback control that is executed at regular intervals. The resin extruder (20) heats and kneads the powder (Y) and a resin (X) supplied thereto from a hopper (21) to form a resin pellet P containing the powder (Y) and the resin (X) mixed uniformly with each other.