PURPOSE: To make it possible to maintain connection strength and narrow a bonding pitch at the same time by excluding plane shape for a wire contact bonding section in a wire contact bonding structure wherein a bonding wire is contact-bonded with a wire contact bonding section of a lead frame or a package of a semiconductor device.

CONSTITUTION: A curved plane is formed on a wire contact bonding section of inner leads 2a, 2b, and 2c so that the connection area for bonding wires 1a, 1b, and 1c may be expanded. Even when an attempt is made to narrow each width of the inner leads 2a, 2b, and 2c, the connection area between the bonding wires 1a 1b, and 1c and the inner leads 2a, 2b, and 2c are equivalent to the case of wider inner leads 2a, 2b, and 2c, which makes it possible to maintain connection strength to a satisfactory extent. A dish-shaped curved plane is formed or a hill-shaped plane is expanded.