An apparatus for checking the length (H) of a chamfer (7) delimited by a first surface (5) and by an edge (S), comprises two feelers (15, 25)—movably connected to a same supporting frame (20)—and respective transducers (16,26). The transducers supply signals (T1, T2) indicative of displacements of the respective feelers along mutually perpendicular directions (Y, X). A checking method includes moving the supporting frame at a constant speed so that, during the movement, one of the feelers scans the chamfer and the other cooperates with the first surface. The signals of the respective transducers are acquired and transmitted synchronously to a processing unit (40) which processes them together with information on the mutual position of the two feelers to obtain the length of the chamfer.