A liquid container includes a body having a tank portion housing liquid, and a liquid supply port at a front side thereof, a piston moving forward inside the tank portion, a piston rod being integrally connected to the piston and extending rearward, the piston rod having an external thread formed in a periphery thereof, an operation cylinder being attached to a rear part of the body in a relatively rotatable fashion, a piston rod guide being adapted to be rotated integrally with the operating cylinder, the piston rod guide having an internal thread hole which is engaged with the external thread of the piston rod, and a ratchet cylinder being fixed in the rear inside the body, the ratchet cylinder having a bore through which the piston rod is pierced in a relatively unrotatable fashion. The operation cylinder is formed with serrated gear teeth at a front end thereof, and the ratchet cylinder is formed with a ratchet gear tooth which is brought into engagement with the serrated gear teeth and adopted to be selectively protruded or retracted in an axial direction, at a rear end thereof.