To provide a high strength member having excellent water resistance and strength and an environment-friendliness.

The high strength member uses a member in which vegetable fibers dispersed by a non-fibrous component and/or a fibrous decomposed product originated on a natural organic material is fixed. This member has a wet tensile strength when the member is dipped in water for 4 hours at room temperature and then lifted from the water of 8 MPa or more, a wet tensile strength when the member is not dipped in the water of 20 MPa or more. The member has biodegradability. The member is useful as the high strength member for a building, fittings, for a furniture, for a transportation or packaging product or for a mechanical or an electrical product.