Providing a novel control agent for soft rot and a novel control method for the same. A compound having no antibacterial activity against Erwinia carotovora but having a control activity against fungi on soil surface, specifically containing, as the active ingredient, a fungicide comprising any of a strobilurin compound such as azoxystrobin and kresoxim-methyl, an azole compound such as triflumizol, cyazofamid, amisulbrom, and thiophanate-methyl, a carboxamide compound such as penthiopyrad and boscalid, a sulfonamide compound such as flusulfamide, an organic chlorine compound such as chlorothalonil, a dicarboximide compound such as procymidone and iprodione, a phenylpyrrole compound such as fludioxonil, an anilinopyrimidine compound such as mepanipyrim, and a guanidine compound such as iminoctadine is the control agent for plant soft rot, which is applied to plant cultivation soil.