To provide a connection structure of a flexible printed board, wherein connecting sections of the flexible printed board can be surely connected without being peeled off and, at the same time, electrically connected in nearly an electrically ideal state and thereby the damage to be caused by poor contact or generation of heat can be reduced as much as possible.

A flexible printed board 1 which is made by stacking a conductor 1B on a cover lay 1A is soldered to be electrically connected to a connected section 3. In a connecting section 1C of the flexible printed board 1, the conductors 1B are adhered to both faces of the cover lay 1A. The conductors 1B on both faces of the cover lay 1A are soldered to be electrically connected to the connected section 3. Preferably, a through-hole 4a is formed in the connecting section 1C of the flexible printed board 1. Solder enters the through- hole 4 and connects the conductors 1B on both faces of the cover lay 1A to the connected section 3.