Rotatable connector device

A rotatable connector device, comprising:

• a fixed-side member;
• a rotatable-side member rotatably attached to the fixed-side member;
• and
• a flat cable accommodated in an annular accommodation space defined by the fixed-side member and the rotatable-side member;
• wherein:
• the flat cable includes a signal flat cable including a pair of signal conductors and a band-like resin covering the pair of signal conductors and also includes a dummy flat cable that is provided on at least one of a front surface and a rear surface of the signal flat cable and is formed of a band-like resin not including a conductor, the signal flat cable and the dummy flat cable being stacked on each other;
• the flat cable further includes adhering means that causes the signal flat cable and the dummy flat cable stacked on each other to adhere to each other;
• and
• a conductor interval between the pair of signal conductors is set to smaller than, or equivalent to, a conductor width of each of the pair of signal conductors.