A clad welding method, which can prevent the occurrence of incomplete fusion, and can cover the surface of a base material over a wide range with a weld metal, while suppressing the dilution of the weld metal, by use of a relatively simple technique, is provided. For this purpose, a welding heat input is increased at a location where one end (10a) of a preceding weld bead (10) and the other end (20b) of a succeeding weld bead (20) overlap, as compared with a welding heat input at a location where the preceding weld bead (10) and the succeeding weld bead (20) do not overlap, to produce a deep penetration portion (12a) involving locally deep penetration (12).