PURPOSE: To improve the quality of a product exterior and to reduce man-hour of repairing the surface.

CONSTITUTION: In the descaling method for steel in which scales produced at the time of hot rolling of seamless pipe, hot rolled steel sheet, etc., are removed by a descaling device 2 using high pressure water, the steel surface is injected with the high pressure water having a discharge pressure of 100kgf/ cm2 that is imparted with a frequency of 500 to 2000Hz and a pulse pressure ratio of 2 or more. Consequently, a descaling performance is greatly improved without an increase in flow rate, and the generation of surface flaws is reduced on steel products.