To secure strength of a suspension arm as well as to secure an arranging space of a connecting part of a rod at a position free to a certain degree.

A suspension arm provided with a rib part 27 in an inside space of an external wall part 20 and arranged with a ball joint part 24 of a control rod 23 is constituted by arranging the rib part 27 so as to circumferentially by-pass an arranging space of the ball joint part 24 of the control rod 23, making this by-passed part a bearing fixing part 29, storing a stopper plate 30 with a bearing part 26 of the ball joint part 24 in a bearing storage chamber 29a of this bearing fixing part 29 and fixing the bearing part 26 by a caulked bent part 29b formed by caulking an inlet side of the bearing storage chamber 29a.