PURPOSE: To retain the end portion of cut filament with a retaining member brought into pressure contact with a backplate by moving a plunger of an electromagnetic solenoid to cut running filament with an edge tool, and then keeping the moving state of the plunger with a small current.

CONSTITUTION: Filament 21 unwound from an unwinding reel is loaded among a contact member 17, an edge tool 19 and a retaining member 20. When the filament 21 is cut, an output electric signal of a filament break detector is changed to LOW, and a transistor Q2 is turned on the feed driving current Vd to an electromagnetic solenoid 12, so that the plunger 13 is moved. When a transistor Q1 is turned on, a current I limited by a resistor R2 is supplied to the electromagnetic solenoid 12. A movable holder 15 is moved by drive of the solenoid 12, and the filament 21 is cut and clamped and held by the contact member 17 and the retaining member 20 to be prevented from hanging down during the supply of current I.