PURPOSE: To make it possible to easily and simply perform classification control, by providing a slip position monitor means, which monitors the position of a slip in a feed path on the basis of a signal issued on every page processing of the slip, in a slip processor and issuing classifying instruction to a slip classifying apparatus on the basis of the output of the slip position monitor means.

CONSTITUTION: A main control part 58 sets a flag 1 to the start bit SP of the page shift memory PSM of a slip position monitor means upon receipt of classifying instruction to start operation of said monitor means. After the start of operation, the flag of the memory PSM is shifted by one bit to right and the main control part 58 refers to the memory PSM. The number of bits from a transfer bit (point) TP to a take-out bit CP are predetermined according to the number (l) of pages from a transfer position A to a burst position B. The main control part 58 investigates whether a flag is present at the take-out point CP (the take-out point CP is turned ON) and, when identifies the presence of the flag, performs classification control. A post-processing control part 35 performs the driving control of a classifying mechanism 42 in response to the classifying instruction to shake a conveyor 40.