To provide a detection device for screen abnormality capable of correctly detecting a screen abnormality such as damage with a simple structure.

A detection device is provided with a primary and secondary AE sensor 11 and 12, used for a comil type separating device 20 pushing out powder from a conical screen 21 by an impeller 22, which is arranged nearby the screen 21 and at a position shifted 90 degrees by bird's eye view of the screen 21, a primary and secondary amplifier 13 and 14 amplifying a detection signal of the primary and secondary AE sensor 11 and 12, and by switching the out put power of the primary and secondary amplifier 13 and 14 into a rotation signal N of the impeller 22, a decision unit 15 deciding an abnormality of the screen 21 such as a damage while the primary AE sensor 11 is detecting a normal noise when the impeller 22 passing by the detection signal of the secondary amplifier 14, and an alarm 16 alarming the generation of an abnormality in the screen 21 based on the decision signal of the decision unit.