Apparatus (3) for pressing an inner ring (2) into a pipe (1) comprising a clamp base (8), a means (5) for pressing the inner ring along the axis of the pipe and a means for generating a force (6), all of them being located on the apparatus body wherein advancement of the pressing means permits an inner ring (2) held in the pressing means to be inserted into the end of a pipe which is held fixed in a clamp base (8). The pressing means has a ring holder (16) at its forward end for detachably holding the inner ring (2) to be inserted. The force generating means are supported by the apparatus body and comprise a pinion (21) engaged with a rack (5a).