To provide a method for producing a preform of a composite material having a complicated shape by using a braid.

This method comprises the following steps: carrying a stress analysis by using a test body of the same shape as that of a composite material intended to be produced (S2); designing a preform of the composite material on the basis of the above results (S6); assembling a braid on a mandrel by using a braider according to the specifications based on the resultant design and producing the preform of the composite material by using the braid (S10).