A safety gas lighter with a loosely mounted striking wheel, comprises a lighter body, topped by a lighter head, an gas release valve, a pressing lever for gas release, a spring, a flint, and a wheel assembly with an axle. The diameter of the axle integrated with the first side wheel is smaller than the diameter of the inner opening of the striking wheel, and the diameter of side wheels are larger than diameter of striking wheel. When in use, because and the diameter of side wheels are larger than diameter of striking wheel, the thumb would strike the side wheels first. For children, because their hands are small, and their strengths cannot be compared with the adults, they can only rotate side wheels, but cannot rotate steel wheels, so the children cannot light fire using the lighter. When adults are using the lighter, their hands will strike the side wheels as well as the striking wheel, to make the side wheels and striking wheel rotate simultaneously. The striking wheel will touch the flint, to generate sparks, and light fires. Because children would not be able to light the fire, only adults can light the fire, the lighter is a safety type lighter.