The direction of change of an analog signal which is digitally displayed on a digital display can be immediately determined at a glance by providing a change-display in the vicinity of the digital display, which digitally displays the analog signal value. The change-display displays whether the analog input signal is increasing or decreasing by comparing the present value of the input signal with a previous value thereof. This comparison may be effected by integrating the input signal and comparing the integrated input signal with the input signal or by differentiating the input signal or by using a sample and hold circuit to hold a previous input signal value which is then compared with the present input signal value.