Miniaturized deburring and/or chamfering tool with a cylindrical guide sleeve (2) in which a blade holder base body (5) is arranged in an exchangeable manner, which has at least one receiving slot (20) for receiving and guiding a blade (6) arranged there, which is leaf-shaped and designed so that it can bend along its longitudinal axis, and which, at its free front end, has a cutting head (7) with a deburring or chamfering blade arranged there, wherein an internal cooling of the blade (6) and removal of shavings from the blade (6) are achieved by the fact that the coolant flows around the blade (6) in the receiving slot (20) on at least two facing sides.