PURPOSE: To easily attain the allocation of parallel elements having the high degree of freedom by allocating parallel elements in plural terminal parts by an allocating instruction outputted from a host part.

CONSTITUTION: Allocation as stop factors and allocation as defective factors are overlappedly allowed to be applied to ten parallel terminals X11 to X20 in a parallel input part 21. Which allocation is to be selected is specified from the host computer side. Namely a selection signal is mask-patterned by the host computer side and the mask pattern is transferred to the terminal side and registered in a set data storing part 27. Data inputted to the parallel terminals X11 to X20 in the input part 21 are applied to AND operation with the mask pattern registered in the storing part 27 and the AND result is sent to the host computer side. Consequently the allocation of parallel elements can be optionally executed.