The object is to provide a transformant which can produce a heterologous protein having a structurally controlled O-linked sugar chain having an O-Man-Gal disaccharide structure, a method for producing the transformant by using Schizosaccharomyces pombe as the host, and provide a host for producing the transformant and a method for producing an O-glycosylated heterologous protein.An Schizosaccharomyces pombe host having no omh1 gene or an inactivated omh1 gene in its chromosomes for producing an O-glycosylated heterologous protein having an O-linked sugar chain having an O-Man-Gal disaccharide structure by expression of the heterologous protein by a genetic engineering technique and subsequent glycosylation of the expressed heterologous protein. A transformant from the host, a method for producing the transformant and a method for producing an O-glycosylated heterologous protein by using the transformant.