A retractable pen including a first barrel, an ink cartridge, a second barrel, a clamping component and a spring; a main body of the ink cartridge, the spring and the clamping component are all located inside the first barrel and the second barrel, the spring is wound on a portion, close to the nib, of the ink cartridge, and the nib in a portion of the ink cartridge can be extended and exposed out of the first barrel; a mounting portion, muff-coupled to the first barrel, is arranged on the clamping component, and the clamping component is rotatable with respect to the first barrel; when the first barrel is muff-coupled to the second barrel, a polygonal neck is formed on a surface where an outer surface of the clamping component comes into contact with the second barrel.