Load distribution method, load distribution device, and system including load distribution device

A load distribution device that receives processing requests from terminals and that allocates and transfers the processing requests to at least one of a plurality of servers. The load distribution device includes a monitoring unit, a request receiving unit, an update server determining unit, a distribution ratio setting unit, a load distribution unit, a notification unit and an update completion detecting unit, whereupon receipt of a notification that the update of the server to be updated is completed, the update server determining unit determines that the update to the server to be updated is completed, determines a new server to be updated and a new server to be updated next, and instructs the distribution ratio setting unit to set the distribution ratios.