Abstract: The invention concerns a fastening band (1) of the belt type or a wristband or bracelet for a portable device (40) for example, including fastening and length adjustment means (5). The fastening band includes an element (6, 42) for indicating the fastening tension thereof that has a specific visual appearance identifiable to the user in order to indicate to the latter when the fastening tension of the band is sufficient for a given application. The fastening band of the present invention is particularly interesting when it is implemented in the form of a wristband for a pulsometer worn on the wrist comprising optical type measuring means. In this application, a fastening tension value sufficient to guarantee proper measurement precision is predefined, the features of the indicator element being adapted to this value in order to indicate to the wearer that he has reached said value when the wristband is being fitted to his wrist.