PURPOSE: To ensure necessary connection strength and isolation distance between metal thin wires.

CONSTITUTION: While a metal thin wire 2 is sequentially led out from a capillary 1, the first part of the metal thin wire 2 is connected with an electrode pad 4, the second part of the metal thin wire 2 is connected to a portion within 150μm away from the end of an outer lead terminal 5 by thermocompression bonding, the capillary 1 is moved to the position spaced 400μm or more from the tip of the outer lead terminal 5, and the third part of the metal thin wire 2 is connected with the position, by thermocompression bonding using ultrasonic waves. When ultrasonic vibration is applied, the metal thin wire 2 is rotated, the distances between the metal thin wires 2 become insufficient, so that the ultrasonic vibration is also used after the rotation of the metal thin wire 2 is stopped by thermocompression bonding. Thereby necessary connection strength and distance are ensured. In paticular, the above method is useful in the case of 5 or more metal thin wires 5 or in cases where the longitudinal direction of the outer lead terminal 5 is inclined to the extention direction of the metal thin wire 2 in a semiconductor device of high density wiring.