To uniformize jet amts. of thermoplastic particles ejected from respective raw material jet nozzles in a spheriodizing treatment apparatus for ejecting a thermoplastic resin into hot air from a plurality of raw material jet nozzles to subject the same to spheroidizing treatment.

A plurality of raw material jet nozzles 28 are attached to the inner periphery of the annular raw material supply head 21 provided on the same axis as a hot air jet nozzle 22 at an equal interval. By connecting raw material introducing cylinders 29 ejecting a solid-gas mixed fluid into the raw material supply head 21 to the outer peripheral direction of the head 21 at an equal interval, the thermoplastic particles ejected into the raw material supply head 21 are uniformized and the jet amts. of the thermoplastic particles ejected into hot air from the respective raw material jet nozzles 28 are uniformized.