A medium loader device includes a first medium loader member configured to load a medium, a second medium loader member usable as an extension of the first medium loader member, and a support member configured to support the first medium loader member and the second medium loader member and to form a storage area capable of storing the second medium loader member between the support member and the first medium loader member. The support member includes a holder configured to hold the first medium loader member such that the first medium loader member moves relative to the support member when the second medium loader member is moved from a usage position where the second medium loader member is used as the extension of the first medium loader member to a storage position where the second medium loader member is stored in the storage area.