To move the position of a table easily and accurately for adjusting a clearance between an upper and a lower edge.

Both the lateral sides of a table 5 are pressed against sideframes 9 on both sides by an energizing means and heldly fixed. Each tap bolt 41 is threadedly engaged in an adjusting block 39 provided on the sideframes 9, and a rear end of each tap bolt 41 abuts on the table 5 so as to be pressable for narrowing a clearance C between an upper edge 21 and a lower edge 7. A drawing bolt 51 arranged at a front end of the adjusting block 39 on an axial line about the same as the tap bolt 41 is abutted against the table 5 through an elastic member 53 to energize for enlarging the clearance C. A lever 45 is connected to each tap bolt 41 and oscillated to slightly rotate each tap bolt 41, and the table 5 is therefore moved by the rear end of the tap bolt 41 so as to narrow or widen the clearance C. Thus the fine adjustment of clearance C can be facilitated.