To reduce the size in a horizontal direction and to provide good electrical performance.

The electronic circuit unit comprises first and second insulating boards 1 and 6 formed on the surfaces of wiring patterns 2 and 7, and passive elements 3 and 8 formed in a thick film in the state in which the elements 3, 8 are connected to the patterns 2, 7 on the surfaces of the first and second boards 1, 6. In this circuit unit, the first and second boards 1, 6 are disposed in the state in which the boards 1, 6 are vertically opposed, and the patterns 2, 7 provided on the first, second boards 1, 6 are connected via a bump 11 made of a metal provided between the first and second boards 1 and 6. Thus, the first and second boards 1, 6 can be vertically disposed. As compared with prior art, the electronic circuit unit in which its lateral size can be reduced the size is reduced in a lateral direction, can be provided.