PURPOSE: To obtain a waveform recorder in which a cursor can be moved or a waveform can be scrolled by the limited number of operating keys and in which the position of the part of a waveform displayed on a screen with reference to a waveform as a whole can be grasped.

CONSTITUTION: In addition to a movement control key 21 and a counting control key 22, a shift key 23 is installed. When the shift key 23 is not pressed, a desired function can be selected by the movement control key 21, and the variable of the function can be changed by the counting control key 22. When the shift key 23 is pressed, a cursor can be moved by the movement control key 21, and a waveform can be scrolled by the counting control key 22.