A protector having an insertion path of a branch wire which branches from a trunk wire of a wire harness where, when the branch wire is not inserted into the branch wire insertion path, the branch wire insertion path can be closed. The wire harness protector includes a closing plate provided integrally with the main body or retrofitted separately, when a branch wire may be present to be inserted through the branch wire insertion path, the branch wire being branched from a trunk wire of a wire harness inserted through the trunk wire insertion path, the closing plate closing a middle or an outlet of the branch wire insertion path, and the closing plate is pressed by the branch wire being inserted and has elasticity to be folded down or vulnerability to be torn.