PURPOSE: To eliminate the loss of time in reversing a printed board by attaching arms having a center slit radially on a disk at intervals of 180 degrees divided by an integer, and disposing two disks facing each other with a distance from each other and with the arms located on the outer sides of the disks.

CONSTITUTION: In the initial condition, a disk 2 is positioned with a positioning pin 7. Arms 1 are stationary with two sets of arms 1 of four sets are always paralle to a belt 13. Non-presence of a printed board 9 at the location of the arm 1 is confirmed with a sensor 11b, a stopper 10 moves down, the printed board 9 is supplied to the arm 1, the stopper 10 moves up, a stopper 14 moves down, and a next board 9 is sent in. A pin 7 retracts, the piston of an air cylinder 8 retracts to move a crank 5, a disk 2 engaged with a drive pin 6 attached to the crank 5 rotates by 90 degrees to turn the board 9 by 90 degrees, the pin 7 advances to fix the disk 2, and the next arm 1 is fixed in a position paralle to the belt 13.