A method for estimating an operator of multiple electrical devices installed in a building, includes receiving, from each of the multiple electrical devices, an operation log indicating that a corresponding electrical device was operated, the operation log including an ID of the corresponding to electrical device and a time at which the corresponding electrical device was operated; receiving first positional information indicating a current position of a terminal of a user; determining, in a case where a distance between the current position and a position of the building is a predetermined distance or less, that the user entered the building; and estimating that the first user is an operator of a first electrical device indicated by an first operation log corresponding to the time at which the first positional information was received, when it is determined that the first user entered the building from outside of the building.