PROBLEM TO BE SOLVED: To provide a sound absorbing structural body capable of decreasing noises and, at the same time, reducing contaminants such as nitrogen oxides or sulfur oxides in atmosphere exhaused from exhaust gases of vehicle or the other. SOLUTION: A sound absorbing material 5 is incorporated into a hollow body 4 constituted of the front plate 1 boring a large number of through-holes 11 thereinto and the rear plate 2 having sound insulating efficiency provided to the rear thereof, uneven surfaces 13 and 22 are formed in the front plate 1 and/or the outside of the rear plate 2, and photocatalyst content layers 6 are formed in the uneven surfaces 13 and 22, and light is irradiated to the photocatalyst content layers 6. Accordingly, since the photocatalyst content layers 6 are formed in the uneven surfaces 13 and 22 formed in the front plate 1 or the outside of the rear plate 2, surface area coming into contact with air gets bigger, and nitrogen oxides, sulfur oxides or the like are effectively eliminated.