PURPOSE: To provide a trimming device in a twin roll continuous casting equipment and a device and a method for treating the trimmed waste which can continuously and stably coil the trimmed waste produced by continuously trimming the hot steel sheet cast through the twin roll continuous caster and rolled.

CONSTITUTION: This trimming device is provided with a dummy sheet 16 having a waste leader part fitted to the tip end part of the steel sheet 2, a trimmed waste coiling roller 8 for continuously coiling the trimmed waste by beforehand coiling the tip part of the waste leader part 32 of the dummy sheet 16 and a trimmed waste cutting device 4 for cutting off the edge parts of the steel sheet 2 to the preset prescribed width. In the trimmed waste coiling roller 8, a coiling angle adjusting device 9 for adjusting the coiling angle of the trimmed waste by rotating the trimmed waste coiling roller 8 in the horizontal direction and a coiling position adjusting device 10 for adjusting the coiling position of the trimmed waste by reciprocatively shifting the trimmed waste coiling roller 8 in the width direction of the trimmed waste, are arranged.