PURPOSE: To provide an inter-beam structure improving the heat resistance of the inter-beam structure of the wing of a space shuttle.

CONSTITUTION: The reinforcing outer plate 3 of the inter-beam structure of the wing of a space shuttle is exposed to the outside air at a high speed at the time of a reentry into the atmosphere. The inter-beam structure of the space shuttle is provided with the box-like reinforcing outer plate 3 having reinforce sections 3a protruded along the longitudinal direction on the right and left of the inside, ribs 5 suspended at a required interval nearly vertically to the longitudinal direction inside the reinforcing outer plate 3 and having flanges 5a at both ends, and channel-like girders 4 kept in contact with the front section and rear section of the reinforcing outer plate 3 along the longitudinal direction at their back sections and fastened to the flanges 5a of the ribs 5 and the reinforcing outer plate 3 by fasteners 6.