PURPOSE: To improve comfortableness by shaping the suspension so that its width vertical to the longitudinal center may be increased gradually and its width horizontal to the longitudinal center may be reduced gradually, thus making an A type suspension arm which links a vehicle body and wheels rigid for a load in the right/left direction and soft for a load in the up/down direction.

CONSTITUTION: The A type upper arm 1 of a double wishbone type suspension is formed out of a ball joint part (wheel-side linking member) 2 consisting of a resin sleeve 21 for ball joint and so forth, bush parts (body-side linking members) 3, 4 consisting of resin sleeves 31, 41 for bushes and so forth, and an arm 5 consisting of fiber reinforcement resin. The arm 5 is provided with arm parts 6, 7 to link the ball joint part 2 with the bush 3, 4. The arm part 6 (or 7) is formed into such a shape as width (b) of the arm part 6 in its vertical direction is increased gradually and width (h) in the horizontal direction is decreased gradually, from the ball joint part 2 and the bush part 3 respectively toward the longitudinal center 61.