Automatic ice making machine and operation method therefor

To restrict the deposition of stain on an ice making unit, and prevent damage to resin components or the like. The above problems are solved by the followings. Ice making water is supplied to the front surface of an ice making plate cooled by refrigerant supplied to an evaporation tube during an ice making cycle to produce ice blocks. During a deicing cycle, deicing water is supplied by opening a water feed valve WV to the rear surface of the ice making plate to be heated by hot gas supplied to the evaporation tube. When a water feed time has elapsed, the water feed valve WV is closed to temporarily stop deicing water supply. After the water feed time elapsed, a cycle, in which the water feed valve WV is opened as much as an intermittent water supply time every time an intermittent stopping time has elapsed to intermittently supply deicing water, is repeated until a deicing cycle completes.