A forward combustion type condensing gas water heater is provided including a burner, a primary heat exchanger, a drain pipe for condensation water, a gathering and discharge device for condensation water, a secondary heat exchanger. The gathering and discharge device and the secondary heat exchanger have center lines different from the primary heat exchanger. Flue gas rises through the primary heat exchanger and passes through the secondary heat exchanger in a direction staggered with respect to the falling direction of condensation water. The condensing gas water heater effectively avoids resistance between the condensation water and the flue gas and prevents the condensation water from flowing to the burner, the combustion chamber, and the ignition pin.