To provide a roll grooving apparatus with structural improvement promoting tracking of a tube during a roll grooving operation.

The roll grooving apparatus for rolling a circumferential groove for the tube is adopted to be mounted on a power drive unit for the axis of a driven and an idler grooving rolls locating in a plane which is one of horizontal and at an acute angle to horizontal so that the weight of a tube between grooving rolls promotes tracking of the groove during a roll grooving operation. A rotatable groove depth gage is mounted on a support member of the apparatus adjacent to a stop member which engages with the support member to determine groove depth, and the gage is displaceable relative to the stop member into and out of a gaging position where the stop member can be set to control the groove depth in a given work.