An environmental state estimation device according to one embodiment of the present disclosure includes an environmental state estimation unit configured to estimate an environmental state of a prescribed area, based on information regarding a surrounding environmental state acquired by a plurality of vehicles in the prescribed area. A method for environmental state estimation according to another embodiment of the present disclosure includes an estimation step of an environmental state estimation device estimating an environmental state of a prescribed area, based on information regarding a surrounding environmental state acquired by a plurality of vehicles in the prescribed area. An environmental state estimation program according to still another embodiment of the present disclosure causes an environmental state estimation device to execute an estimation step of estimating an environmental state of a prescribed area, based on information regarding a surrounding environmental state acquired by a plurality of vehicles in the prescribed area.