A mold for injection molding includes a design-surface-side mold which is capable of forming a design surface of a resin molded product and a non-design-surface-side mold which is capable of forming a mold cavity with the design-surface-side mold. A convex portion is provided in any one of the design-surface-side mold and the non-design-surface-side mold so as to protrude toward the other one. The mold for injection molding is configured to be capable of switching a first mold closing state in which the convex portion is present from any one of the design-surface-side mold and the non-design-surface-side mold over the other one and a second mold closing state in which the convex portion is not present from any one of the design-surface-side mold and the non-design-surface-side mold over the other one.