A writing instrument, including: a writing lead for the writing instrument; wherein the writing lead has a polygonal sectional shape, the corner parts of the writing lead being ridge lines along a longitudinal direction thereof; a chuck configured to sandwich and chuck the writing lead, wherein the chuck includes: a first chuck pawl including a tip formed in a wedge shape having an acute angle, wherein the tip includes a first wall surface, a first inclined surface, and a first tip edge formed therebetween; wherein the first tip edge is a ridge line of the tip of the first chuck pawl; wherein the first inclined surface is formed inclined so as to form an acute angle with the first wall surface; and wherein the first tip edge comes into point contact with one of the corner parts of the writing lead, or line contact with a surface of the writing lead, to press the writing lead so as to apply first contact stress to the writing lead; and a second chuck pawl which presses the writing lead so as to apply, to the writing lead, second contact stress that is lower than the first contact stress, and the first contact stress applied by the first chuck pawl to the writing lead is configured such that, when a prescribed impact is applied to the writing lead, the contact portion of the writing lead subjected to the first contact stress fractures. a writing lead for the writing instrument; wherein the writing lead has a polygonal sectional shape, the corner parts of the writing lead being ridge lines along a longitudinal direction thereof; a chuck configured to sandwich and chuck the writing lead, wherein the chuck includes: a first chuck pawl including a tip formed in a wedge shape having an acute angle, wherein the tip includes a first wall surface, a first inclined surface, and a first tip edge formed therebetween; wherein the first tip edge is a ridge line of the tip of the first chuck pawl; wherein the first inclined surface is formed inclined so as to form an acute angle with the first wall surface; and wherein the first tip edge comes into point contact with one of the corner parts of the writing lead, or line contact with a surface of the writing lead, to press the writing lead so as to apply first contact stress to the writing lead; and a second chuck pawl which presses the writing lead so as to apply, to the writing lead, second contact stress that is lower than the first contact stress, and the first contact stress applied by the first chuck pawl to the writing lead is configured such that, when a prescribed impact is applied to the writing lead, the contact portion of the writing lead subjected to the first contact stress fractures. a first chuck pawl including a tip formed in a wedge shape having an acute angle, wherein the tip includes a first wall surface, a first inclined surface, and a first tip edge formed therebetween; wherein the first tip edge is a ridge line of the tip of the first chuck pawl; wherein the first inclined surface is formed inclined so as to form an acute angle with the first wall surface; and wherein the first tip edge comes into point contact with one of the corner parts of the writing lead, or line contact with a surface of the writing lead, to press the writing lead so as to apply first contact stress to the writing lead; and a second chuck pawl which presses the writing lead so as to apply, to the writing lead, second contact stress that is lower than the first contact stress, and the first contact stress applied by the first chuck pawl to the writing lead is configured such that, when a prescribed impact is applied to the writing lead, the contact portion of the writing lead subjected to the first contact stress fractures.