PURPOSE: To provide a flexible wiring board whereon even an element with a flexible lead can be mounted.

CONSTITUTION: A flexible wiring board 2 has a slit 3. An opening C is formed by displacing two regions A and B separated by the slit 3 in the direction of arrows f1 and f2, and flexible leads 1a to 1d of an element 1 are put in the opening C and the leads 1a and 1d are inserted in lead insertion grooves 2a and 2d of the flexible wiring substrate 2. Therefore, when the leads 1b and 1c are inserted to the lead insertion grooves 2b and 2c, the opening C of the slit 3 is closed and positioning is executed so that tips of leads overlap with soldering lands 6a to 8a of the flexible wiring substrate mutually. Therefore, each lead and each land are combined performing soldering for each land and regions A and B are fixed by performing soldering for lands 10a and 10b simultaneously. Therefore, in this method, it is not required to reciprocate the element 1 in the direction of an arrow D and to bend a flexible wiring based as in a conventional method.