The directional coupler

Without identifying for providing direction when mounted on the circuit board laminate of the directional coupler (12), the laminate (12) by a plurality of insulating layers (16) formed by laminating. The main line (ML) and the sub lines (SL) built into the laminate (12), and comprising a helical portion (Sp1, Sp2) having a central axis (Ax1, Ax2) parallel to the z-axis direction, and the main line ( ML) and the sub lines (SL) are electromagnetically coupled to each other. The main line (ML) and the sub lines (SL) have the same shape, and disposed in the same region of relative y-axis direction.