PURPOSE: To provide a highly reliable thermocompression soldering method, which can perform a soldering work at low cost without complicating the constitution of a device and at the same time, can make reliably the connection between fellow connection electrodes and the connection between the connection electrodes and leads without separating from each other.

CONSTITUTION: A thermocompression soldering device is formed into a constitution wherein leads 24 are superposed on continuous electrodes 22 of a printed board 21 and thereafter, a press member 26, which has insulation properties and at the same time, is set its melting point or softening point higher than the melting point of solders 23, is placed on the leads 24, then, a thermocompression tool 25, which is always heated, is pressed on the member 26 to melt the solders 23 and at the same time, the member 26 is secured on the board 21, then, the tool 25 is separated from the leads 24.