Abstract: A rotary-type pen includes a barrel unit, a refill seat and a rotary drive unit. The barrel unit includes a barrel defining a barrel axis and having an inner barrel surface formed with a helical guiding unit surrounding the barrel axis. The refill seat is guided by the guiding unit to move along the barrel axis for moving a refill relative to the barrel when the refill seat is rotated relative to the barrel. The rotary drive unit includes a rotary knob and a force transmitting member. The rotary knob is retained rotatably on the barrel and is operable to rotate relative to the barrel about the barrel axis. The force transmitting member extends from the rotary knob into the barrel and is coupled co-rotatably to the rotary knob. The force transmitting member drives the rotation of the refill seat in the barrel.