The application relates to a microorganism having weakened activity of a LacI family DNA-binding transcriptional regulator protein, and an L-glutamic acid production method using same. A Corynebacterium sp. microorganism having weakened activity of a LacI family DNA-binding transcriptional regulator protein has remarkably increased L-glutamic acid productivity, and thus the microorganism can produce L-glutamic acid in a yield higher than that of a conventional microorganism by using same.