PURPOSE: To reduce the level of noise and facilitate manufacturing by a stabilizer wherein the stabilizer body is housed in a case on the bottom side, and the horizontal cross-sectional ratio of the stabilizer body to the case is set not higher than a specified value.

CONSTITUTION: A stabilizer body 2 is arranged on the side of a bottom surface 1a of a case 1, and the ratio of horizontal cross-sectional area S2 of the stabilizer body 2 to horizontal cross-sectional area S1 of the case 1, i.e., the horizontal cross-sectional area ratio S2/S1 is set not higher than 0.7. A compound 4 is injected into the case 1 through the upper opening. By so doing, aggregates 5 of higher specific gravity are settled toward the bottom surface 1a of the case 1 by the force of gravity, whereby the aggregate mixing rate in the compound 4 around the stabilizer body 2 becomes higher than that of the upper opening part. As a result, the surrounding of the stabilizer body 2 is more heavily rigidified than other parts to absorb vibrations of the core portion, thus alleviating the level of noise. The horizontal cross-sectional ratio S2/S1 not higher than 0.7 promotes settlement of the aggregates 5 causing them to be localized at the bottom of the case 1 due to the difference in specific gravity, so that the manufacturing is facilitated.