The invention provides a film supply mechanism and a sealing and cutting apparatus. The film supply mechanism comprises a positioning part which is used for bearing a packaging film roll; the positioning part is provided with a positioning space used for accommodating the packaging film roll; and the packaging film roll is placed on the positioning part and at least one part of the packaging film roll is located in the positioning space. When the film supply mechanism is used, a worker places the packaging film roll in the positioning space of the positioning part; when the film supply end of the packaging film roll is subjected to the drawing force, the packaging film roll can rotate relative to the positioning part, so that a packaging firm can continuously slide outwards from the positioning space. Since the mounting operation is not needed when the packaging film roll is replaced and the packaging film roll can be simply placed on the positioning part, so that the packaging film roll replacement has the characteristics of convenience and rapidness. Therefore, the intensity of the worker is reduced, the working efficiency is improved, and the work reliability of the sealing and cutting apparatus can be ensured.