The present invention relates to a transfected mammalian host cell whose ability to secrete a foreign protein has been enhanced by using a foreign gene expression vector having a promoter derived from a human gene, and a method for producing the foreign protein using the host cell. A method for enhancing the production of a foreign protein to be used in a pharmaceutical protein product in a host cell such as a cultured mammalian cell is provided. A promoter derived from a human gene having a promoter activity higher than that of a cytomegalovirus (CMV) promoter in a host cell such as a cultured mammalian cell is provided.