Method of repairing composite material and composite material

A method of repairing a composite material that is formed of fibers and resin in a plate shape and has a to-be-removed frustum-shaped portion having a diameter enlarging from a back side toward a front side, the composite material being bonded with a repair material replacing the removed portion, comprising the steps of:

• removing, from the front side, at least a first portion of a top face of the frustum-shaped portion so as to form a through hole that passes completely through the composite material in a thickness direction while leaving a support wall protruding inward in a radial direction from a periphery of the through hole, the first portion extending from the top face so as to include at least a projected area of the top face on a bottom of the frustum-shaped portion;
• then sealing the back side by placing a sealing plate on the support wall to close the through hole while the back side is accessible from the front side via the through hole, the sealing plate being inserted from the front side into the through hole formed by the removing step;
• then placing the repair material through an adhesive on the composite material where the frustum-shaped portion has been removed;
• and
• then evacuating in a state in which the front side is sealed.