PURPOSE: To establish a means for stably mass producing hot-dip galvannealed steel sheet having high quality regardless of kind of steel to the base material without needing a special new equipment.

CONSTITUTION: At the time of pickling and descaling to a hot-rolled steel sheet for galvanizing, shot blasting treatment is executed and successively, if necessary, the surface is brushed or after executing cold-rolling having ≥30% rolling ratio, desirably, heating treatment in strong oxidizing atmosphere to this hot- rolled steel sheet in a continuous hot-dip galvanizing line, and then, the hot-dip galvanizing is executed. This steel sheet is heated to execute the alloying treatment. Even in the case of being the high strength steel sheet having chemical composition of 0.002-0.2% C, ≤2.0% Si, 0.5-2.5% Mn, ≤0.1% P and the balance Fe with inevitable impurities in the base material, the stable treatment can be executed.