To provide a method for operating a vertical crusher suitable for minutely crushing a slag, and to provide a device therefor.

A vertical crusher 1 is provided with a crushing roller 3, auxiliary roller and a rotary table 2, and crushes a slag charged on the rotary table 2 by the crushing roller 3 after consolidating with the auxiliary roller. In the vertical crusher 1, a ratio of the diameter of the crushing roller 3 to that of the rotary table 2 is ≤0.45, and at least two crushing rollers are disposed. According to the operation method for the vertical crusher having a vibration sensor S1 for measuring the vibration of a crusher body, the crusher is composed to lower the revolution of the rotary table 2 when the detection value of the vibration sensor S1 exceeds a previously set threshold value. Thus, when minutely crushing the slag, the crusher prevents abnormal vibration caused by the slip of the crushing roller 3 on a raw material layer, thereby crushing the raw material efficiently.