To provide a power generation facility capable of appropriately avoiding engine stall at a time of power failure of a commercial electric power system 1 and continuing electric power supply from a power generator 2 to an important electric power load 6a with a structure which can be materialized simply and at low cost in a system interconnection with the power generator 2.

An engine stall avoidance means 21 raising equivalent ratio of air fuel mixture M supplied to a combustion chamber of an engine 3 for a certain period of time at a time of detection of power failure by a power failure detection means 11.