A settlement terminal device according to the present invention includes: a first information processor that is placed in a housing which is gripped by an operator, and is provided with a first user interface (first touch panel) on one surface (operation display surface) of the housing; a secured second information processor that is placed in the housing, and is provided with a tamper-resistant second user interface (second touch panel), which can perform a securable operation, on one surface of the housing; and one light transmitting member (surface panel) that is disposed to cover a surface of the first user interface and a surface of the second user interface.