PROVIDED IS A NOVEL CONTROL AGENT FOR SOFT ROT AND A NOVEL CONTROL METHOD FOR THE SAME. THE CONTROL AGENT FOR SOFT ROT OF A PLANT CONTAINS 3-CHLORO-N-(3-CHLORO-5-TRIFLUOROMETHYL-2-PYRIDYL)-ALPHA, ALPHA, ALPHA-TRIFLUOROMETHYL-2-PYRIDYL)-ALPHA, ALPHA, ALPHA-TRIFLUORO-2, 6-DINITRO-P-TOLUIDINE AS AN ACTIVE INGREDIENT, WHICH IS APPLIED TO PLANT CULTIVATION SOIL.