(57) A tape-shaped switch (500) is provided on a base part (410). Coil springs (460) support a ring-shaped rotational drive section (450) on the position opposed to the switch (500), biasing the same away from the base part (410), so that that the rotational drive section (450) may move toward and from the base part (410). First buffers are provided in association with the switches (501) of the tape-shaped switch (500), respectively. A flange (313) extends outward from the disc-shaped table plate (311) of a jog table unit (310) and is mounted on the rotational drive section (450). When the user depresses the jog table unit (310), moving the same downward, at least one of the switches (501) is closed. The motion of the jot table unit (310) is reliably detected because it is detected at a position outside that part of the jog table unit (310), which is depressed so that good feeling of the operation can be obtained.