A desired shape can be easily realized, and a decrease in strength can be inhibited. A method for producing a composite material includes: an insertion step of inserting an inner member in which a second reinforcing fiber is impregnated with a resin into a space of an outer member that is formed of a woven first reinforcing fiber extending in an undulating manner, the outer member including an opening that is provided at at least one end portion and the space that communicates with the opening; and a composite material forming step of forming a composite material in which the outer member and the inner member are joined to each other by curing the resin of the inner member to join the outer member and the inner member to each other.