To provide an auxiliary chamber type gas engine capable of imparting vibration to a check valve by a small structure.

The auxiliary chamber type gas engine 1 includes a main combustion chamber, an auxiliary combustion chamber 3 communicating with the main combustion chamber, a fuel gas supply passage 9 extending from the auxiliary combustion chamber 3, and the check valve 4 arranged in the fuel gas supply passage 9 so as to allow the inflow of gas to the auxiliary combustion chamber 3 by passing through the fuel gas supply passage 9 and regulate the outflow of the gas from the auxiliary combustion chamber 3 by passing though the fuel gas supply passage 9. The check valve 4 includes a valve housing 5 forming a part of the fuel gas supply passage 9, a valve element 6 movably arranged in the valve housing 5, a spring 7 for urging the valve element 6 toward a valve seat 5g arranged in the valve housing 5, and a moving member 8 relatively movably installed in the valve element 6 and capable of imparting vibration to the valve element 6 by colliding with the valve element 6.