Abstract: An overhead cable wherein a sectional shape of an outer circumferential surface formed by outermost members is a polygon inscribing a circle of a diameter d (mm), sides of the polygon are formed as substantially flat surfaces connecting adjoining vertexes, vertexes of the polygon inscribing the circle are cut away to form arc-shaped grooves having a radius R (mm) and having a depth H (mm) from the vertexes, and the arc-shaped grooves are formed in spirals in the outer circumference of the overhead cable in a longitudinal direction of the overhead cable at predetermined pitches, the diameter d of the overhead cable being in a range of 18 to 52 (mm), and the outer circumferential surface formed by the outermost members being formed so that a number N of vertexes of the polygon and the diameter d satisfy a condition defined by the following formula: