A flat cable assembly for a rotary connector device includes a first lead block, a first flat cable, and a second flat cable. The first lead block includes a first lead block body and a first conductor that includes a first exposure surface exposed from the first lead block body and is attached to the first lead block body. The first flat cable includes a first cable end portion connected to the first exposure surface so as to extend from the first exposure surface in a first direction. The second flat cable includes a second cable end portion connected to the first exposure surface so as to extend from the first exposure surface in a second direction, which is different from the first direction.