An air conditioning system controller is provided, which performs an air conditioning of a house through an air conditioning controller. The air conditioning system controller includes an in-house power generation amount obtaining section for obtaining a power generation amount generated by a natural energy power generator (for example, a solar power generation panel), an electric power amount obtaining section for obtaining a consumed electric power amount used in the house, a comparing section for comparing the power generation amount obtained by the in-house power generation amount obtaining section with a consumed electric power amount obtained by the electric power amount obtaining section and an air conditioning controlling section for controlling the air conditioning controller according to a comparison result provided by the comparing section.