A power generation system (200) of the present invention comprises a power generation portion (202) configured to generate power, a load power detecting means (205) configured to detect a load power supplied from a power source including the power generation portion to a load, an operation stop determination means (209) configured to stop a power generation operation of the power generation portion based on the load power detected by the load power detecting means and a stop condition; and a stop condition setting means (220) configured to set the stop condition, wherein the stop condition setting means sets different stop conditions in a plurality of time periods, and wherein the operation stop determination means stops the power generation operation of the power generation portion based on each of the different stop conditions set by the stop condition setting means and the load power detected by the load power detecting means.