PURPOSE: To display all information wanted by a user to obtain from the small number of a terminal by incorporating an electrochromic indicator, a data converting circuit and a decoder driver circuit for indicator in a cash card.

CONSTITUTION: When writing, series data inputted from a series inputting terminal 3 are converted to parallel data by a data converting circuit 5 and formed to an electrochromic indicator driving signal by a decoder driver circuit 6 for an electrochromic indicator and displayed in the electrochromic indicator 1. When erasing, similarly, it is enough to give a driving signal that erases entirely display of the indicator 1. As the number of terminals is small, structure is simple, and as power source for driving the circuit 5 and circuit 6 is supplied from outside, no battery is needed for the card.