Provided is a hydrogen occluding alloy powder having an ideally activated surface state where oxide and hydroxide precipitated on the surface of said powder have been removed quickly with a simple means. The method for surface treating a hydrogen occluding alloy powder involves agitating a hydrogen occluding alloy powder containing Ni and Mg with an Ni content from 35 to 60 wt% in a lithium hydroxide aqueous solution (first process). Then the hydrogen occluding alloy powder is agitated in an alkali metal hydroxide aqueous solution containing at least either one of sodium hydroxide and potassium hydroxide (second process).