Provided are a soundproof structure and an opening structure which is easy to be manufactured, has a light weight, and is capable of absorbing sound in a wide frequency bandwidth. The soundproof structure includes a tubular member and a film member arranged so as to block a hollow portion of the tubular member. Assuming that a wavelength corresponding to a resonance frequency in a single film vibration element of the film member is λa, lengths from a position at which the film member is attached to two opened end surfaces of the tubular member are L1 and L2, an opened end correction length is δ, and n is an integer of 0 or more, at least one of (λa/4−λa/8)+n×λa/2−δ≤L1≤(λa/4+λa/8)+n×λa/2−δ or (λa/4−λa/8)+n×λa/2−δ≤L2≤(λa/4+λa/8)+n×λa/2−δ is satisfied.