Abstract: An internal-combustion type of gas lighter is provided including a cylindrical lighter housing enclosing a lighter body having a fuel gas reservoir therein; a fuel gas ejection nozzle in communication with the fuel gas reservoir via a valve; a lid permitting ignition of a combustible mixture when open and preventing ignition when shut; an orifice member positioned downstream of the fuel gas ejection nozzle to increase the flow rate of fuel gas ejected from the fuel gas ejection nozzle; a mixing tube positioned downstream of the orifice member, the mixing tube having air injection apertures to suck air under a negative pressure caused by a jet flow of fuel gas from the orifice member, thereby providing a fuel gas-and-air combustible mixture; a diffuser positioned downstream of the mixing tube to decrease the flow rate of the combustible gas mixture and to diffuse the combustible mixture; an ignition actuator to operate a piezoelectric element for igniting the combustible mixture; a combustion cylinder position