To prevent so-called a cutout (partial defect due to insufficient filling) in the case of molding a foot wear bottom integral with an instep cover, for example, by an injection molding process and to simultaneously improve external appearance after molding.

The method for manufacturing a footwear comprises the steps of forming slit-like recess grooves 2s on an outer surface of a last mold 2 opposed to mold mating surfaces 3a of side molds 3, bringing an instep cover 5 hung from the mold 2 into contact with the surfaces 3a of the molds 3, and simultaneously surrounding a lower part of the mold 2 with a bottom mold 4 to form a space for molding a foot wear bottom. When a foot wear bottom material is filled in the space, substantial gas bleeding part is formed between the grooves 2a having weak adhesive properties, the peripheral instep cover 5 and the surfaces 3a upon rising pressure in the space. The gas bleeding is expedited, and passage of the material is prevented to eliminate generation of a flash.