A paint cartridge (21) is formed by a baggy tank (23) and a tank accommodating cylindrical body (22) formed of a transparent hollow tubular body. The baggy tank (23) is provided in the tank accommodating cylindrical body (22) as a dual structure formed by an inner bag (28) and an outer bag (29). A paint chamber (30) inside the inner bag (28) is connected to a feed tube (14), and an extruding liquid flows into and out of an extruding liquid chamber (32) between the outer bag (29) and the tank accommodating cylindrical body (22). A detector (33) which is visually observable from outside the tank accommodating cylindrical body (22) is provided on the inner bag (28) and the outer bag (29) of the baggy tank (23). As this detector (33), a material is used whose shape, pattern, or hue changes due to contact with the paint which leaks when the inner bag (28) has broken or the extruding liquid which leaks when the outer bag (29) has broken. In consequence, it is possible to detect the breakage of the inner bag (28) and the outer bag (29) by visually observing a change in the detector (33) from the outside.