To provide an aligning method for electric circuit device, an alignment reference formation device, an electric circuit device, and a printed board wherein a minute recessed part is formed on side and front surfaces of an electric circuit device and a printed board and its center of gravity is taken as a reference original point for alignment so that their positions in height direction are measured with precision, for improved precision in alignment in height direction, allowing high-precision mounting position control.

A minute recessed part 1 used as a reference point for alignment is formed with laser on a printed board 3 and an electric circuit device 2 mounted on the printed board 3 with soldering 4 as well as on the side surface of the printed board 3, with the shape of the minute recessed part 1 being such shape as circle or square whose center of gravity is easily acquired.