A 5kW class Stirling engine generator has been developed with the aim of constructing a system mainly for service use. The Stirling engine is built up as a 2-piston type with driving mechanism. It has a hot cylinder and a heat-exchanger cylinder in which a regenerator and a cooler are installed, and the both cylinders are connected by a heater made by U-shape tubes. The developed Stirling engine generator is unified hermetically because of including a PM synchronous generator in the driving mechanism. From the results of performance test, electric power is 3.92kW and efficiency is 31.4% based on thermal heat into the engine. It is effective in environmental preservation and energy saving to apply the developed Stirling engine generator to a power generation and heat supply system with heat source of wastes and wood biomass, since a heater shape is suitable for absorbing heat form combustion gas.