PURPOSE: To facilitate soldering to objects which are hardly solderable, by adhering a chromium soldering material on a base plate and applying a nickel plating layer thereon then soldering an object to be soldered thereto.

CONSTITUTION: A nickel plating layer alone or both layers 4 of a nickel plating layer and a tin plating layer are provided on the surface of the nichrome foil 1 which is a soldering object stuck by means of an adhesive agent to a base plate 3 of a fuel sensor for announcing the remaining amt. of fuel A in an automobile by an electrical signal. Lead wires which are objects to be soldered are soldered to the layer 4.