A flexible printed circuit board has first and second connection portions 18 and 19 where contacts are exposed and first and second path portions 16 and 17 where conductor patterns 11 are arranged that connect the contacts 11a and 11b of the first and second connection portions 18 and 19 together. The first and second path portions 16 and 17 are formed so as to have substantially symmetrical shapes with each other about a predetermined straight line, and the flexible printed circuit board is folded up along the straight line C1 and C2. Alternatively, a flexible printed circuit board has a conductor pattern 11 formed between first and second insulating sheets 12 and 13, and has a shielding conductor 14 fixed to the second insulating sheet 13. The flexible printed circuit board is folded up with the second insulating sheet 13 outside so that the conductor pattern 11 is enclosed inside the shielding conductor 14.