Communication cable, wire harness, and method for manufacturing communication cable

A communication cable comprising:

• a signal wire constituted by a pair of insulated wires each having a conductor and an insulating coating covering an outer circumference of the conductor;
• and
• an insulating external layer covering an outer circumference of the signal wire,
• wherein a characteristic impedance is within a range of 100±10Ω,
• at least one of the insulating coating and the insulating external layer is made of a flame-retardant resin composition that contains:
• a polymer component containing at least one selected from a polyolefin and an olefin-based copolymer, the polymer component further containing a polar functional group comprising at least one selected from the group consisting of:
• a carboxylic acid group, an acid anhydride group, an epoxy group, a hydroxyl group, an amino group, a silane group, an acrylic group, and a methacrylic group;
• a flame retardant containing a brominated flame retardant;
• and
• a flame retardant auxiliary containing antimony trioxide,
• an aggregate containing the flame retardant auxiliary has an aggregation diameter of 50 μm or less,
• when a content of the polymer component is taken as 100 parts by mass, the flame-retardant resin composition contains:
• the polar functional group in an amount of 0.05 parts by mass or more and 15 parts by mass or less,
• the brominated flame retardant in an amount of 20 parts by mass or more and 50 parts by mass or less, and
• the flame retardant auxiliary in an amount of 5 parts by mass or more and 25 parts by mass or less.