The invention concerns a method and device for adjusting the fitting depth of a tool in a tool-holder, in particular in a tool-holder to be banded. The method is characterized in that it consists in performing a prior calibration of a sensing assembly (2) by positioning a sensing slide (4) of said assembly (2) into a bore (V) of a calibrating support (1) and by re-setting a viewing means of said sensing assembly (2), then in positioning the sensing assembly above a tool-holder and moving the adjustable stop of said tool-holder towards the sensing slide (4), so as to determine a travel thereof corresponding to the required fitting depth. The invention is applicable in the field of the environment of machine-tools, more particularly comprising tool-holders to be banded.