To provide a small and easily attachable/detachable cover that can cover a back loop part and a shoulder strap mounting part while maintaining functionality of the back loop part as well as fitting of the shoulder strap and that prevents the hair from being caught in the strap.

A flap-side cover 1 attachable to the base of an outer flap and a belt-side cover 5 are vertically connected, while a slit 12 for inserting a handle 54 or the like of a satchel is formed in the middle of the connecting part. In the middle of the cover 1, there is installed a projecting piece 3 protruding downward and, in the middle of the cover 5, a cover piece 10 is provided that protrudes upward to engage with the projecting piece 3 and to cover the slit. In the cover 5, a covering portion 6 having a horizontal width similar to the cover 1 and having a forked center lower part is integrally connected at the forked part with a folded portion 7 in which folds 7a, 7b foldable right and left from the forked part are extendedly provided.