PURPOSE: To provide a melt processing device of ends of thermoplastic flexible material which makes it possible to achieve shortening of processing time, improvement in finished quality, liberalization of process, unnecessariness of skill, reduced processing cost, improvement of work environment and prevention of fire.

CONSTITUTION: There are provided a supporting member 3 for clamping and supporting near an end 2 to be treated of a thermoplastic flexible material 1 which is deformable at least in a radial direction, a vibrating member 4 which has therein a recess 5 facing the end 2 for insertion thereof and generates ultrasonic wave vibration for melting the material 1, and a press member 6 which drives at least one of the member 3 and the member 4, and also causes the end 2 to be inserted and urged into the recess 5.