To remove Fe in a leach liquor fed to cleaning-electrolyzing stages in wet type zinc refining at high precision.

When zinc is leached with acid from roasted ore essentially composed of zinc oxide in a first leaching tank 10, pulp discharged from the first leaching tank 10 is subjected to solid-liquid separation with a first thickener 11, zinc is further leached with acid from leaching residue separated with the first thickener 11 in a second leaching tank 12, and the pulp discharged from the second leaching tank 12 is subjected to solid-liquid separation with a second thickener 13, utilizing a buffer tank 14 of temporarily storing the leaching residue, the sum total of the leaching residue contained in the first thickener 11 and the leaching residue contained in the second thickener 13 is held to a desired range.

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