Abstract: Coaxial filter having at least one of the internal and external conductors which is divided into sections (S.sub.1 to S.sub.4) separated by breaks having to form of annular slits whose thickness is very slight in relation to the wavelength.Each section comprises at least one reactive tuning element such as an open or short-circuited coaxial line portion and at least one switch element located in the vicinity of the corresponding break in order selectivity to short-circuit the said break or bring about the insertion of the corresponding reactive tuning element in response to electronic control devices.Application to telecommuncations.