L-Cysteine is produced by culturing a microorganism having an ability to produce L-cysteine and modified so that expression of emrAB, emrKY, yojIH, acrEF, bcr, or cusA gene should be enhanced in a medium to produce and accumulate L-cysteine in the medium and collecting the L-cysteine from the medium. Genes coding for novel L-cysteine-excreting proteins are identified, and utilized for breeding of L-cysteine-producing microorganism to provide a novel method of producing L-cysteine.