A sheet storage apparatus (for example, banknote handling machine includes: a holding unit (for example, each holding member) configured to hold a storage bag in a state where an opening portion of a banknote storage bag is opened or in a state where the opening portion of the banknote storage bag is sealed; a regulation unit configured to selectively regulate access to the banknote storage bag held by the holding unit; and a control unit configured to control the regulation unit so as to allow access to the banknote storage bag held by the holding unit in a state where the opening portion of the banknote storage bag is opened when a predetermined condition is satisfied.