Abstract: Pipe cutting apparatus (2) in which a pipe is clamped in a holder (4) and cut transverse to its longitudinal axis by a cutting head 6. The cutting head (6) is supported on the holder (4) and is rotatable around the pipe to cut the pipe wall with a blade (38). The blade (38) is advanced radially by an indexing mechanism (40) in response to rotation of the cutting head (6) around the pipe. The indexing mechanism (40) has a snail cam (44) rotatable to advance the blade (38) in response to indexing movement of a ratchet (48) controlled by a pawl (50) mounted on the holder (2) to advance the ratchet (48) on completion of each revolution of the cutting head (6). The blade (38) is withdrawn when the pipe is cut and has a stop (60) that engages a cut-out (61) in the snail cam (44) to block indexing movement of the ratchet (48) and re-set the cutting head (6).