A printed wiring board comprising: a connection part that is to be connected to a projecting portion of an external member by soldering, wherein the connection part comprises: a first hole in which the projecting portion is inserted; a main land to which the projecting portion is soldered; a metallic pattern that is drawn from the main land ; and a sub-land that is connected to the main land through the metallic pattern , wherein the main land is constructed with a metallic film configured to cover a peripheral region of the first hole not in a back face but only in a front face of the printed wiring board comprising the front face and the back face , the front face to which the soldering is performed and the back face on a side opposite to the front face , and the metallic film is not formed on a sidewall forming the first hole , and wherein the sub-land is constructed with a metallic film configured to cover a sidewall formed by a second hole piercing the printed wiring board and a peripheral region of the second hole in both the front face and the back face of the printed wiring board , wherein the sub-land is not electrically connected to a wiring pattern formed on the back face , and the sub-land is electrically independent of the wiring pattern, wherein the wiring pattern is a circuit and the metallic pattern does not extend onto the sidewall forming the first hole nor onto the back face to connect the main land in the front face and the sub-land in the back face . a connection part that is to be connected to a projecting portion of an external member by soldering, wherein the connection part comprises: a first hole in which the projecting portion is inserted; a main land to which the projecting portion is soldered; a metallic pattern that is drawn from the main land ; and a sub-land that is connected to the main land through the metallic pattern , a first hole in which the projecting portion is inserted; a main land to which the projecting portion is soldered; a metallic pattern that is drawn from the main land ; and a sub-land that is connected to the main land through the metallic pattern , wherein the main land is constructed with a metallic film configured to cover a peripheral region of the first hole not in a back face but only in a front face of the printed wiring board comprising the front face and the back face , the front face to which the soldering is performed and the back face on a side opposite to the front face , and the metallic film is not formed on a sidewall forming the first hole , and wherein the sub-land is constructed with a metallic film configured to cover a sidewall formed by a second hole piercing the printed wiring board and a peripheral region of the second hole in both the front face and the back face of the printed wiring board , wherein the sub-land is not electrically connected to a wiring pattern formed on the back face , and the sub-land is electrically independent of the wiring pattern, wherein the wiring pattern is a circuit and the metallic pattern does not extend onto the sidewall forming the first hole nor onto the back face to connect the main land in the front face and the sub-land in the back face . <EOS>