To provide a setting gauge capable of easily and simply setting a depth stopper.

In the setting gauge 21 to set a depth stopper 6 provided a hand piece 1 to having a connection mechanism to detachably connect a pin-like tool 4 to the hand piece 1, in particular, for root canal therapy, to easily and simply set the depth stopper 6, the setting gauge 21 has a connection device to connect/position the setting gauge 21 and at least one scale provided on a setting gauge body 22 on the hand piece 1. The scale is extended parallel to the depth stopper 6 and its advancing path at the position of the setting gauge 21 connected to the hand piece 1.