A bicycle component (e.g., a rear derailleur) is basically provided with a base member and an axle. The axle includes a base supporting part supporting the base member for pivoting about a center axis of the axle and a base attaching part projecting outwardly of the base member for fixedly attachment to a bicycle frame. The base supporting part and the base attaching part overlap to define a coupling interface in which either a fixing element is disposed between the coupling interface of the base supporting part and the base attaching part or one of the base supporting part and the base attaching part is deformed with an interference fit. The base supporting part is formed of a first material with a first specific gravity. The base attaching part is formed of a second material with a second specific gravity that is higher than the first specific gravity.