PURPOSE: To intend to decrease the number of total selectors by forming matrices by multistage, and by decreasing the number of selectors which are provided at the part of multistage matrices.

CONSTITUTION: Matrices consists of small matrix groups L10, L20∼ in the X axis direction and small matrix groups M1∼Mn in the Y axis direction. For the small matrix M1, selectors SW are provided at all intersection points of drop circuits m1y1∼m2ym and selection lines m1x1∼m1xm. On the other hand, for the small matrices L10, L20∼, the selectors SW are provided at only diagonal intersection points of selection lines m1x1∼m1xm and local lines l1x1, l1x2∼ of the small matrix M1. Thus, matrices are formed by multistage and the number of selectors of the other is decreased. Therefore, the number of total selectors can be decreased.