Abstract: An extruding mechanism for a tubular bag and a method of extruding the contents of a tubular bag are provided, by which a sealing material or the like is extruded and discharged from a tubular bag with an extruding gun for a cartridge container, and which reduces the amount of discarded waste, thereby serving as one solution to environmental problems. The extruding mechanism includes an extruding gun having a holding base, and a stationary holding plate disposed on a front end portion of the holding base. The holding plate is provided with a notched portion opened upward. An extruding rod is equipped at its leading end with a pressing plate. A cylindrical member having a cylinder body is set on the holding base and accommodates the tubular bag and is opened at both ends, and a piston body is inserted into the cylinder body.