To reduce feeling of tiredness at feet by using a cushion structural body having a density, a ventilation factor, and a compression recovery factor in specific ranges, in which elastic composite short fibers composed of inelastic polyester crimped short fibers, a thermoplastic elastomer having a low melting point in a specific range, and a polyester polymer are dispersed and mixed and heat-fixed points are scattered.

As shock absorbing material, a cushion structural body of a density of 0.005-0.15g/cm3, a ventilation factor of 50-100cc/cm3/sec., and a compression recovery factor of 50-95% is used. In the cushion structural body, elastic composite short fibers 2 composed of inelastic polyester crimped short fibers 1 as a matrix and a thermoplastic elastomer having a 40-150°C lower melting point than that of the polymer composing the matrix and a polyester polymer are dispersed and mixed to be exposed in such a way that the half of the surfaces of the elastic composite short fibers is occupied with the thermoplastic elastomer. In addition, flexible heat fixed points A, B are scattered in the cushion structural body.