The present invention relates to a heat storage material composition comprising 20 to 100% by weight of a heat storage material, 80 to 0% by weight of crystalline polyolefin (B) and 50 to 0% by weight of an elastomer (C), and the heat storage material described above contains a side chain-crystalline polymer (A), wherein the heat storage material described above comprises preferably a higher .alpha.-olefin polymer (a) containing 50 mole % or more of higher .alpha.-olefin having 10 or more carbon atoms and a petroleum wax (b) in which a melting point (Tm) is higher by 10.degree. C. or more than that of the polymer (a). Provided is a heat storage material composition which has less bleeding and stickiness and is excellent in stability at high temperature and which can meet a change in temperature such as a difference in room temperature when applied to a material for floor heating and can avoid a heating state deviated to high temperature or low temperature.