To reliably remove earth and sand, soil, and small mass from a grizzly by constantly driving a movable grizzly bar for preventing the earth and sand, soil, and small mass from adhering to and clogging the grizzly and moving the movable grizzly bar in a special movement manner even in the case the earth and sand, soil, and small mass adhere to the grizzly.

The grizzly apparatus comprises fixed grizzly bars and movable grizzly bars arranged at equal intervals in a large number of rows. The upper ends of the fixed grizzly bars are fixed in a fixing frame and the movable grizzly bars are installed in a manner that the fixation base parts are fixed in an installation shaft installed in one end of a supporting arm whose the other end is journalled with the fixing frame and the other ends of the movable grizzly bars are opened. The grizzly apparatus further comprises an output shaft and an eccentric shaft rotated by deceleration transmission from a driving power source. The movable grizzly bars are made possible to reciprocate back and forth along the rotating circumference of the supporting arm through an installation shaft installed in the one end of the supporting arm corresponding to the distance of the rotation movement of the eccentric shaft.