MULTI-LAYER PRINTED CIRCUIT BOARD

Ground via provided in an end portion of a multi-layer printed circuit board so as to suppress a leakage of magnetic field from the end portion of the board causes a problem that a digital circuit of high density cannot be mounted on the board due to necessity of area for locating the ground via. Further, a case of using solder plating for the end portion of the board causes a problem that manufacturing process is added and that numbers of days and costs for manufacturing the multi-layer printed circuit board are increased. In a multi-layer printed circuit board has a plurality of ground layers and at least one signal layer, the signal layer in which a signal pattern is wired at an end portion of the multi-layer printed circuit board is sandwiched between upper adjacent and lower adjacent ground layers, and the upper adjacent and lower adjacent ground layers are connected to each other by recessed conductors at the end portion thereof. In addition, an interval between the recessed conductors is not larger than λ/8 of a higher harmonic frequency as an operable frequency.