PURPOSE: To cut a bar-like extrusion molded body made of ceramics or metal powders and plastic easily, make a cut face smooth without causing die wear, chipping, and occurrence of cut chips, prolong a service life of a cutting blade, cut the bar-like extrusion molded body without stopping a feed of it, and change cutting length freely.

CONSTITUTION: A cutting device of bar-like extrusion molded body consists of a pair of feed conveyors 5 which move a molded body 1 in a feed direction a, a cutting machine 2 which moves up and down a cutter blade 24 attached on an ultrasonic vibrator 22 and a horn 23 by an air cylinder 41, an adjuster 31 which determines the cutting position of the molded body 1, an arm 3 which is provided with a touch sensor 33 at a tip section 32 in the shape of L character, and a guide rod 4 which can move the molded body 1 in a return direction (b) which is the reverse direction to the feed direction a by the air cylinder 41 after cutting the molded body 1 and returns to its original position by a stopper 42. The molded body 1 is cut to a predetermined dimension by a cutter blade by a displacement device having the arm 3, and then the cutting machine 2 is returned to the predetermined normal position to cut the molded body 1 one after another.