PURPOSE: To remarkably facilitate recognizing display contents in case the extent of movement in both of positive and negative directions or the like is displayed with an origin position as a reference point, by adding some circuits to a well-known up/down counter to display a positive or negative sign and an absolute value.

CONSTITUTION: The positive or negative sign is stored in a flip flop 4; and if the positive sign is stored in the flip flop 4, a switching output 3b generated by a host device 3 is transmitted to a switching input 1b of a counter 1 as it is. If the negative sign is stored in the flip flop 4, the switching output 3b generated by the host device 3 is logically inverted and is transmitted to the switching input 1b of the counter 1. Light emitting diodes 10a are horizontally arranged on the left of a numerical value display device, and light emitting diodes 10b are vertically arranged orthogonally to light emitting diodes 10a. Thus, a sign '-' is displayed on a sign display device 10 when only light emitting diodes 10a are lit, and a sign '+' is displayed there when light emitting diodes 10a and light emitting diodes 10b are lit together.