PURPOSE: To make it possible to form a thermoplastic resin composition which is light and sufficiently elastic and excels in temperature characteristics, strength, processability, abrasion resistance, etc. and suited for, especially, soles of footwear, by mixing 1,2-polybutadiene with a polyolefin and a specified olefin polymer.

CONSTITUTION: This thermoplastic resin composition is prepared by mixing 5W90wt.% 1,2-polybutadiene (a) of a 1,2-bond content ≥70% with 5W90wt.% at least one polyolefin (b) and 5W90wt.% at least one polar group-containing α-olefin polymer (c). As component (b), propylene is particularly desirable. As component (c), a copolymer of an α-olefin with a polar vinyl monomer is desirable, and as the α-olefin, ethylene is desirable. An ethylene/vinyl acetate copolymer is particularly desirable as component (c).