PRINTED WIRING BOARD

PROBLEM TO BE SOLVED: To secure the strength of bonding to a lead, by forming a recess of a shape similar to the external form of a through hole opposed to the land provided on a printed wiring board. SOLUTION: Lands 18 made of copper foils on a substrate 12 are provided in parallel in conformity with the leads 14 of IC 10. Then, a through hole 22 round in plan view is provided in each land 18. The distance from the outermost through hole 22a to the corresponding land 18 is shorter than that form the other through holes 22 to the respective lands 18. Only the outermost land 18 is made a round land 24 which has a recess 26 in the shape of a curved surface in plan view only at its section opposed to the through lone 22a. The strength of bonding to this round land 24 is not different at all from the strength of bonding to a usual land 18. Moreover, through the through hole 22a is provided close to the round land 24, the shape of the recess 26 of the round land 24 is curved, so enough distance to the through hole 22a can be kept.