A shaft body for a pencil lead (including a color pencil lead) or a shaft body for a cosmetic such as a rod-shaped cosmetic including an eye liner, an eyebrow pencil, or an eye shadow, which has the same ease of shaving as a conventional wood shaft and has a low impact on the environment. The shaft body for a pencil or a cosmetic according to the present disclosure is a shaft body for a pencil or a cosmetic constituted by coating a pencil lead or a rod-shaped cosmetic with a shaft body material composition, and the shaft body material composition contains at least a naturally-derived constitutional material and a naturally-derived binder.

A shaft body for a pencil lead (including a color pencil lead) or a shaft body for a cosmetic such as a rod-shaped cosmetic including an eye liner, an eyebrow pencil, or an eye shadow, which has the same ease of shaving as a conventional wood shaft and has a low impact on the environment. The shaft body for a pencil or a cosmetic according to the present disclosure is a shaft body for a pencil or a cosmetic constituted by coating a pencil lead or a rod-shaped cosmetic with a shaft body material composition, and the shaft body material composition contains at least a naturally-derived constitutional material and a naturally-derived binder.

A writing instrument part that improves the releasability of a core pin is provided. In a writing instrument part by the insert molding method in which a wooden barrel material made of natural wood flour and a water-soluble resin binder is injected into a mold, the wooden barrel material and a core pin having a paper straw inserted therein are integrated, and a two-layer structure having a paper straw layer as an inner layer and a wooden barrel layer as an outer layer is formed.

Recycled natural material such as an extender material including at least one type of powder derived from a biomass resource and having a particle size of 2 mm or less, a machinability-improving material comprising a thermoplastic solid having a melting point of 40 C. or higher, and a binding material may be molded in a predetermined shape such as a rod shape, a plate shape, a tube shape, a block shape, or a sheet shape. The extender material/the machinability-improving material/the binding material may be in mass proportions of 20 to 65/15 to 55/10 to 50.

Recycled natural material such as an extender material including at least one type of powder derived from a biomass resource and having a particle size of 2 mm or less, a machinability-improving material comprising a thermoplastic solid having a melting point of 40 C. or higher, and a binding material may be molded in a predetermined shape such as a rod shape, a plate shape, a tube shape, a block shape, or a sheet shape. The extender material/the machinability-improving material/the binding material may be in mass proportions of 20 to 65/15 to 55/10 to 50.