A flat cable, which has an insulating coating composed of a polyester resin composition, the composition containing: (A) 100 parts by weight of a thermoplastic aromatic polyester; (B) 10 to 120 parts by weight of a polyester block copolymer composed of: 20 to 80 wt% of a hard segment whose main component is poly(tetramethylene terephthalate) that is composed of an acid component in which terephthalic acid occupies 60 mole% or more and a diol component in which tetramethylene glycol occupies 60 mole% or more; and 80 to 20 wt% of a soft segment whose main component is a polyester that is composed of an acid component in which an aromatic dicarboxylic acid occupies 60 mole% or more and a diol component of a long-chain diol having 5 to 12 carbon atoms; and (C) 1 to 50 parts by weight of an olefin-acrylate copolymer modified by a glycidyl compound.
