To provide an electronic circuit unit in which migration between wiring patterns is prevented and shorting between the wiring patterns does not exist.

In the electronic circuit unit, the wiring pattern 2 arranged in a circuit board 1 on which a semiconductor component 10 is loaded is provided with a plurality of connection parts 3 which are disposed by leaving intervals and formed of metal materials for connecting terminals 10b and a plurality of first conductive patterns 4 which are connected to the connection parts 3, are extended and are formed of silver materials arranged by leaving the intervals. First coating parts 7 formed of glass materials are formed on the first conductive patterns 4 positioned near the semiconductor component 10 so that they surround the outer periphery of the semiconductor component 10. The first conductive patterns 4 in a high density state are covered with the first coating parts 7. Consequently, migration (transition of silver) is prevented, and shorting between the wiring patterns 2 is eliminated.