Pen and pen case thereof

The utility model discloses a pen case. The pen case comprises a shell, a rotary component and a cylindrical pen core connecting block, wherein the inner wall of the shell has a circular cross section; the rotary component is arranged in the shell in a rotating way; the cylindrical pen core connecting block is arranged in the shell; the rotary component comprises a rotary rod part which is exposed out of the shell and an extension part which extends into the shell; the shell is provided with internal thread; the peripheral surface of the pen core connecting block is provided with a spiral chute which is matched with the internal thread; and the pen core connecting block can axially and movably clamped between the inner wall of the shell and the extension part and is circumferentially positioned on the extension part. Due to such arrangement, the pen case disclosed by the utility model can effectively prevent the problem of making surrounding environment dirty. The utility model also discloses a pen comprising