A wire harness manufacturing method includes a conduction path inserting step of inserting one or a plurality of conduction paths from one end of a resin-made tubular exterior member to the other end thereof, and an exterior member working step of performing post-working on one or a plurality of parts of the exterior member, after the conduction path inserting step. The exterior member working step includes forming a convex-shaped part when viewed from an inner surface side of the exterior member by performing the post-working using heat on an outer surface side of the exterior member. The convex-shaped part is a vibration suppressing part to reduce a play rate of the conduction path in the exterior member and suppress a vibration of the conduction path.