DESCRIPTION HOLLOW STABILIZER, AND STEEL PIPE FOR HOLLOW STABILIZERS AND METHOD OF PRODUCING THE SAME Technical Field [0001] The present invention relates to a hollow stabilizer used for a vehicle such as an automobile, and a steel pipe for hollow stabilizers used as a material for the hollow stabilizer and a method of producing thereof. Background Art [0002] Stabilizers are applied to vehicles such as automobiles for the purpose of securing the running stability of vehicle bodies during high speed running while suppressing the rolling of vehicle bodies during cornering. The stabilizer is conventionally manufactured by processing a solid material such as a steel bar into an intended shape. In recent years, hollow stabilizers using a hollow material such as a seamless steel pipe or an electric resistance-welded steel pipe are increasingly used for the purpose of promoting weight reduction. [0003] In the case of changing the design from a solid stabilizer to a hollow stabilizer, the outer diameter ofthe hollow stabilizer necessarily becomes larger than that of the solid stabilizer in order to maintain the same roll rigidity. As a result, the generated stress with respect to the same load becomes larger in the hollow stabilizer, and therefore, it is necessary to increase a wall thickness/outer diameter (t/D) ratio for suppressing an increase in the generated stress. [0004] Thin-walled hollow stabilizers with a tD of from 0.1 0 to 0.17 are conventionally applied to compact cars with low design stresses. However, in order to apply hollow stabilizers to a large car with a high design slress, t/D is required to be increased. For this purpose, a method of producing a hollow stabilizer in which an electric resistance-welded steel pipe is subjected to diameter-reduction hot rolling and then drawing (for example, see Patent Document I), and a thick-walled steel pipe for hollow stabilizers produced by subjecting an elcctric resistance-welded steel pipe to diameter-reduction hot rolling (for example, see Patent Document 2) have been suggested. [0005] In the case of the hollow stabil~zerf, atigue fracture was sometimes generated from the inner surface wh~chis absent in the solid stabilizer. This is because fatigue fracture is generated from a decarburized layer on the inner surface even when the fatigue strength of the outer surface of the steel pipe is improved by increasing the strength to the steel pipe. In 1 order to solve this problem, a steel pipe for hollow stabilizers in which the tiD is 0.20 or more and the generation of the decarburized layer on the inner surface is suppressed has been suggested (for example, see Patent Document 3). [0006] Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 2000-233625 Patent Document 2: International Publication No. WO 2007-023873 Patent Document 3: JP-A No. 2007-270349 SUMMAI