The present invention provides a modified promoter, an expression vector and a transformant each containing the promoter, and a method for producing a gene product of interest using the transformant. The invention provides a modified promoter, including a nucleotide sequence of a promoter derived from bacterium belonging to the genus Bacillus in which at least one nucleotide sequence selected from the following has been modified: a nucleotide sequence represented by SEQ ID NO: 1; a nucleotide sequence equivalent to the nucleotide sequence represented by SEQ ID NO: 1, except that one or a plurality of bases therein are substituted, deleted, added or inserted; and a nucleotide sequence having a sequence identity of 70% or more with respect to the nucleotide sequence represented by SEQ ID NO: 1.