PURPOSE: To provide a printed wiring board capable of preventing defective soldering when mounting narrow pitch semiconductor packages.

CONSTITUTION: This printed wiring board comprises a printed board 1, first and second foot print patterns formed closely on the printed board, said first foot print pattern having a first region and a second region, and the second foot print pattern having a third region and a fourth region. And the width of the second region is formed narrower than the width of the first region in the direction almost normal to the direction of the first and second regions; also the width of the third region is made narrower than the width of the fourth region in the direction almost normal to the direction of the third and fourth regions; solder paste is formed without flowing out to the first and fourth regions; and the second and third region are the region where the outer leads of electronic parts mounted on the board come into contact with each other.