Abstract: A device fixed on a measuring instrument provides access to the terminals of a microwave component in order to measure scattering, noise or output power parameters. In order to minimize the length of connections between the access lines of the device and the input and output terminals of the component to be measured, two access blocks which carry the access lines are positionally adjustable with respect to the component to be measured in such a manner as to permit two degrees of freedom in relative-spacing displacement and in lateral translational displacement. Irrespective of the type of component to be measured (chip, package, or hybrid circuit), the component is carried by an insert block placed between the two access blocks and having dimensions equal to those of the component.