PURPOSE: To provide an apparatus for cutting fibers to shorter lengths comprising fiber cutting blades and a press roller for pressing fibers to a blade, and capable of indicating the timing to replace a blade with a monitor comprising a sensor for detecting their angular positions, a sensor for detecting a roll pressure and a means for displaying the states of the blades.

CONSTITUTION: A cutter reel assembly 10 has plural blades 12 mounted for cutting fibers to shorter lengths and a press roller 11 for pressing fibers to a blade 12. Extendable fibers like tows are cut to shorter lengths by using a fiber cutting apparatus, in which the cutter reel assembly 10 is provided with a sensor 18 for detecting the angular positions of the assembly, a sensor 34 for detecting the force applied on the press roller 11 via fibers on the reel assembly 10 and a means 41 for displaying the states of the blades 12 in the cutter reel assembly 10 as a function of the angular positions and forces applied on the press roller 11.