Anti-drying whiteboard pen

The invention provides an anti-drying whiteboard pen. A refill is compound cylinders, a thin cylinder is disposed at the front end, and a thick cylinder is arranged at the rear end. A nib comprises a water delivery pen core and a water delivery pen core fixer, and external threads are arranged on the outside of the water delivery pen core fixer. A connector is arranged between the nib and the refill and is a circular cylinder, two symmetrical circular protrusions are arranged at the top end, and two circular pits corresponding to the circular protrusions are formed in the tail end of the thin cylinder of the refill, so that the connector is prevented from slipping. Internal threads are arranged on the inner wall of the connector, the water delivery pen core fixer can be fixed on the connector through rotation. A spring is arranged on the connector, a sliding button is arranged on a pen holder and is connected with the connector through a connection rod, and the nib is exposed by sliding the button towards the nib and is contracted into the pen holder by sliding the button reversely. A circular partition layer is arranged at the top end of the pen holder, and two blocking plates are arranged in the circular partition layer and are in a string sheet shape. The two blocking plates are distributed symmetrically in the circular partition plate, and magnets are arranged at the string edges of the blocking plates. The blocking plates can be closed automatically after the nib is contracted to close a pen hole.