The terminal holding device includes an attaching unit to be attached to a vehicle, a holding unit which removably holds a terminal device in such a manner that a display unit of the terminal device is exposed and which includes a contact surface to be contact with the terminal device, an acceleration sensor which detects acceleration in a direction from a side of the contact surface to a side opposite to the contact surface, and a supplying unit which supplies a detection signal of the acceleration sensor to the terminal device.