To obtain a styrene-based thermoplastic elastomer composition that suppresses the increase in the hardness of a styrene thermoplastic molding and can increase the mechanical strength without damage to the rubber elasticity, and provide a styrene-based thermoplastic molding.

A styrene-based thermoplastic elastomer and an acid-modified styrene-based thermoplastic elastomer are mixed to form a modified styrene- based thermoplastic elastomer and a fibrous liquid crystal polymer is formulated to the resultant modified styrene-based thermoplastic elastomer to give the objective composite thermoplastic elastomer composition.