According to a conventional art, a large number of adjustment pads are necessary if impedance mismatching is large or characteristic impedance is low. Such a large number of the adjustment pads needs to secure a large area for arrangement of the adjustment pads preliminarily. However, occupation of a large area induces an interference with other distributed constant circuit. The present invention concerns a distributed constant circuit capable of adjusting the impedance matching between a conductor line such as micro strip line disposed in a small area and an electronic device in order to solve the above-described problems. This distributed constant circuit intends to achieve the impedance matching between the characteristic impedance of the conductor line and the load impedance or drive impedance of the electronic device by bringing the adjustment tab moving on a substrate into a contact with the conductor line.