[Object] To provide a hybrid system of which overall efficiency is improved.[Solution] A hybrid system of the invention includes: a fuel cell device; and a thermoacoustic cooler. The thermoacoustic cooler 14 includes: a thermoacoustic energy generating section 20 in which thermoacoustic energy is generated by a temperature gradient between a high-temperature side and a low-temperature side; and a cooling section 21 in which a function of cooling is performed in the low-temperature side using the temperature gradient between the high-temperature side and the low-temperature side which is produced when the thermoacoustic energy transmitted from the thermoacoustic energy generating section 20 is converted into energy. The system is configured to cause exhaust gas emitted from the fuel cell device to flow through the high-temperature side of the thermoacoustic energy generating section 20. Therefore, it is possible to achieve the hybrid system of which overall efficiency is improved.