BOARD PROCESSING UNIT

PROBLEM TO BE SOLVED: To detect this when a belt is cut by arranging a belt cut detecting means for detecting a cut of the belt. SOLUTION: When a timing pulley 12-1 rotates by rotating a motor, timing belts 5-1, 5-2 and timing pulleys 12-2, 12-3 rotate by interlocking with it to rotate a rotary body. For example, when the timing belt 5-1 is cut, an idler pulley 13-1 stops, so that a dog 15 does not pass between a phoromicrosensor 16, and a pulse signal is not sent out so as to detect that the timing belt 5-1 is cut. In this case, the timing pulley 12-3 rotates by rotation of the other uncut timing belt 5-2 to transmit torque of a motor to the other rotary body. Thus, a processing object board continuously rotates without impairing rotational torque so much, so that the board is continuously processed.