PROBLEM TO BE SOLVED: To install a bag-shaped container in a gun-type dispenser for cartridge, and to control insertion of a part of the container into a space between a sleeve and a piston when the container is pushed by the piston of the dispenser.SOLUTION: The container holder can be attached to a gun-type dispenser for discharging a content by pushing the inside of an exchange type cartridge by a piston 50 in place of the cartridge, and holds a deformable container A. The container holder includes a cylindrical sleeve 80 installed in an installation portion 10 with the container attached thereto, and a piston cover 81 attachable to/detachable from the front end of the piston 50, and slides in the sleeve to push the container A. The sleeve has a lid portion 82 opened/closed to take out/push in the container. The piston cover includes a circular front part 100 with its center matched with the axis of the piston, and an insertion control portion 101 for controlling any insertion of a part of the container into a space between the piston cover and the sleeve.