A composite material structure manufacturing jig (10) is used when manufacturing a composite material structure by adhering prepreg to a framework structure including a frame component that includes a channel extending along a longitudinal direction of the frame component. The composite material structure manufacturing jig (10) is inserted in the channel of the frame component and used therein. The jig (10) includes a tubular body (11) formed of an elastic material containing a reinforcement fiber, the body (11) including a trapezoidal transverse section that is a cross section orthogonal to a longitudinal direction of the body (11), the trapezoidal transverse section including an upper base and a lower base longer than the upper base. An inner surface of the body (11) is coated with an inner peripheral film (16) serving as a gas barrier layer.