To provide an apparatus for treating mud capable of stopping a rotating drum at a predetermined position while viewing the rotating drum without inching operation.

The apparatus for treating mud which makes a reformed earth by mixing a mud with a solidifying agent comprises a drum driving device 12 for giving a roller 11 disposed on a base frame 6 a rotating power, a rotating drum 1 supported on the roller 11, a mud introducing part 2 for supplying the mud in the rotating drum 1, a solidifying agent introducing part 3 for supplying the solidifying agent in the rotating drum 1, a reformed earth discharging part 4 for discharging the reformed earth in the rotating drum 1, a proximity switch 60 for detecting a rotational angle of the rotating drum 1, an operation panel 5 having an automatic stopping switch 50 for automatically stopping the rotating drum 1 at a set rotational angle, and a controlling device 70 for stopping the rotating drum 1 at the set rotational angle by out-putting a stopping signal to the drum driving device 12 on the basis of a detected signal in-put from the proximity switch 60 after an operation signal from the automatic stopping switch 50 is in-put.