Provided is a thermochromic writing instrument 1, comprising: a writing body 9, storing a thermochromic ink therein, stored in a barrel 2; an operation body provided in the barrel 2 to be operated to longitudinally move the writing body 9; a nib 91 of the writing body 9 configured to be capable of appearing from a front end of the writing instrument, wherein the writing instrument 1 further includes a friction unit 10, rubbing handwriting in the thermochromic ink and capable of thermally changing the color of the handwriting by frictional heat generated at that time, and at least one clip body 7 as the operation body, the friction unit 10 is provided at a rear end of the barrel 2, and the clip body 7 is provided in an area other than the rear end of the barrel 2.