PURPOSE: To make it possible to give variety to the finished state of a fiber in a hot air suction type apparatus for heat treatment of fiber.

CONSTITUTION: This apparatus is composed of a feeder 2, an inlet holding unit 3, suction drum units 4, an outlet holding unit 5, a discharge unit 6, rotary drive units 7 and collision units 8. The inlet holding unit 3 and the outlet holding unit 5 are set respectively under the preceding step and under the latter step of the suction drum units 4 and the suction drum units 4 are subjected to normal-rotation transfer by the rotary drive units 7 while being rotated in the normal and reverse directions. Each collision unit 8 for forcing treated materials (A) sent from the suction drum units 4 to collide with each other is set between the suction drum unit 4 and the holding unit adjacent thereto so as to apply a flexural rubbing treatment and a collision rubbing treatment to the treated materials (A).