A porous sound absorbing structure according to the present invention includes an outer material 2 having a smooth curved shape, an inner material 3 having an uneven shape with a perimeter thereof combined with a perimeter of the outer material 2 to form a hollow portion S between the outer material 2 and the inner material, and a reinforcing plate material 4 having a large number of through holes 5, the reinforcing plate material being attached to a surface of the inner material 3 on the side of the hollow portion S in such a manner that an air layer is formed between the reinforcing plate material and the surface. A sound absorbing property is given to an interior of the hollow portion S by the reinforcing plate material 4.