<p>It is possible to reduce the danger of information leak caused by remaining cache data. An information processing device (1) includes: data communication means (17) which performs data communication with a server computer (4) via a data communication network (5); storage means (15) which can temporality store data transmitted and received at least to/from the server computer (4); and information processing means (12) which executes information processing based on the data transmitted or received to/from the server computer. The information processing device (1) further includes: external storage device connection means (3) to which an external storage device (2) capable of data read-out and write-in is detachably connected; and shift means (12) which shifts temporary storage of data transmitted/received to/from the server computer (4) from the storage means (15) only to the external storage device (2) in accordance with mounting of the external storage device (2) on the external storage device connection means (3).</p>
