The present invention is to provide a printer and an ink tank therein. The ink tank includes a tank body, a first pillar, a resilient component, a lid, a second pillar and a waterproof moisture-permeable assembly. An ink filling port and a first opening are formed on an upper side of the tank body. The first pillar and the resilient component are disposed in the first opening and forming an openable intake passage cooperatively. The lid covers on the upper side of the tank body, a second opening and a second pillar are formed on the lid. The second pillar includes a communicating portion, and a waterproof moisture-permeable assembly is disposed on the lid and communicating with the communicating portion through the second opening. The present invention is to prevent the waterproof moisture-permeable assembly from being stuck by ink when the printer is not in printing operation.