To provide a support method for controlling addition of an agent, capable of supporting various controls on addition of the slime control agent to a white water system in papermaking equipment from a remote place.

In this support method for controlling the addition of the agent, an addition detector 61 detects the start of an operation of a unit which adds the agent and operates at specified intervals of quiescent periods, when the slime control agent is added from a storage tank 80 to the papermaking white water system 84. A flow meter 62 detects an addition amount of the agent at a time when the start of the operation of the unit is detected. Thus, data of the detected addition amount are transmitted to a support server which controls the addition of the agent and is positioned at the remote place, so that a time during which the agent in the storage tank 80 is consumed is estimated based on the transmitted data. Further, a notice for requesting filling-up of the slime control agent is transmitted to a controller of the papermaking equipment, when the estimated time becomes shorter than a period which is determined based on a time required for filling up the slime control agent and preliminarily set and during which the filling-up is allowed to be postponed.