Provided is a transformant which can produce lactic acid with a high productivity without requiring neutralization with an alkali and is excellent in both of lactic acid production capability and growth ability and its production process, and a method for producing lactic acid by using the transformant.A transformant containing from 3 to 5 copies of a lactate dehydrogenase gene derived from human and introduced into a Schizosaccharomyces pombe host, wherein a gene that is a part of a group of genes encoding pyruvate decarboxylase of the Schizosaccharomyces pombe host is deleted or inactivated. A transformant characterized by providing a cell concentration of at least 4.0 g (on a dry cell weight basis)/L of a culture broth prepared by inoculating cells, at an initial cell concentration of 0.04 g (on a dry cell weight basis)/L, into a 500 mL Sakaguchi flask containing 100 mL of a liquid culture broth which includes 1% of yeast extract, 2% of peptone and 6% of glucose, and then cultivating 20 hours at a temperature of 32° C. under shaking conditions of 110 rpm and 7 cm stroke, and providing a lactic acid concentration of at least 80 g/L of a fermentation liquor prepared by inoculating cells obtained by cultivating 20 hours under the above-described conditions, at an initial cell concentration of 36 g (on a dry cell weight basis)/L, into a 11.1% glucose aqueous solution, and then fermenting 3 hours at a temperature of 32° C. under shaking conditions of 110 rpm and 7 cm stroke. A method for producing lactic acid by using these transformants.