Indicator device for a hearing loop, arranged to be permanently installed at a location from which it is clearly visible for a user of the hearing loop during such use. The indicator device includes a minimum magnetic field setting unit, a hearing loop detection unit arranged to measure the current field strength of a magnetic field produced by the hearing loop, an interpretation device arranged to translate the detected field strength, in relation to the minimum field strength, to produce a corresponding current relative intensity signal, as well as a variable display unit arranged to display a visible signal indicating the value of the current intensity signal.