The cartridge includes a liquid containing portion containing a liquid, a liquid supply portion, an arrangement portion having a bottom wall in which an opening through which the liquid introduction portion is inserted is formed, and a film peelably attached to the arrangement portion while covering the opening portion, in which the arrangement portion further has a mounting element cooperating with the printing apparatus, and the film is arranged at a position where the film is interposed between the printing apparatus and the mounting element when a mounting process is performed in a state in which the film is attached to the arrangement portion.