To provide a connection structure of a highly reliable flat circuit body which has an improved joining intensity of the connection part.

The connection structure is that a terminal part 11A of FFC 11 which has a plurality of conductors 12 arranged in parallel pinched by base films 13, 14, is joined to a wiring terminal pattern 16 formed on the surface of a wiring board 15 by soldering, where, a bottom side coating film 13 which is joined to the wiring terminal pattern 16 in the terminal part 11A of FFC 11 is separated by an equivalent length of a solder leveler 18 area on the wiring terminal pattern 16, and also the upper side base film 14 in the terminal part 11A is separated at the end side of the flat film circuit body 11 as from the bottom side base film 13, and formed so as to cover a part of the wiring terminal pattern 16.