To provide a sub-chamber type gas engine, which is low-cost, and in which a supply amount of fuel gas is accurately controlled.

The sub-chamber type gas engine 1 includes: cylinders 2a to 2d; pistons 3 movably housed in the cylinders 2a to 2d and forming main combustion chambers 2a1 to 2d1 in the cylinders 2a to 2d; sub-chamber members 4 formed with injection holes 4a2 to 4d2 communicated with the main combustion chambers 2a1 to 2d1 and sub-chambers 4a1 to 4d1 communicated with the main combustion chambers 2a1 to 2d1 through the injection holes 4a2 to 4d2; fuel supply pipes 5 communicated with the sub-chambers 4a1 to 4d1; check valves 6a to 6d provided in the fuel supply pipes 5 to permit supply of fuel gas to the sub-chambers 4a1 to 4d1 and to restrict a back flow from the sub-chambers 4a1 to 4d1; collecting pipes 7a, 7d to which upstream sides of the plurality of check valves 6a to 6d corresponding to the plurality of cylinders 2a to 2d of different operation period timings are collected; and fuel supply devices 8a, 8b provided to the collecting pipes 7a, 7b to regulate supply amounts of fuel gas to the sub-chambers 4a1 to 4d1.