A resonant sound absorbing device of a gas turbine combustor includes a plurality of resonance chambers independently disposed side by side in an axial direction of the gas turbine combustor so as to communicate with a gas passage of the gas turbine combustor via acoustic holes. The plurality of resonance chambers include n related resonance chambers each satisfying: 0.9 × ∑ i = 1 n ⁢ F i n ≤ F i ≤ 1.1 × ∑ i = 1 n ⁢ F i n ( A ) where n is an integer of 2 or more, and Fi is a peak frequency corresponding to a maximum sound absorbing ratio of the ith related resonance chamber of the n related resonance chambers.