Provided is a composite material structure enabled to be reduced in weight. The composite material structure includes a front section (3a) extending in one direction and formed as a composite material made of fiber reinforced plastics, a rear section (3c) separated from the front section (3a) by a predetermined space, extending in the one direction, and formed as a composite material made of fiber reinforced plastics, and access panels (5) provided between the front section (3a) and the rear section (3c) and having a dimension in the one direction shorter than the front section (3a) and the rear section (3c). The access panels (5) are fixed to the front section (3a) and the rear section (3c) in an orthogonal direction substantially orthogonal to the one direction and set to be displaceable in the one direction and are removable.