A liquid container includes a container body (2) formed with a liquid supply port (3), and a container-side fixing structure (7) which releasably regulates movement of the liquid container in.an outward pulling direction in cooperation with apparatus-side fixing structure provided for the container mounting part in a state where the liquid container is mounted onto the container mounting part. The container-side fixing structure (7) has a guide groove (16) into which a fixing pin of the apparatus-side fixing structure can be inserted, and which guides the fixing pin in mounting and removal operations of the liquid container to and from the container mounting part. The guide groove (16) includes a fixing part (18) which engages the fixing pin to regulate the movement of the liquid container (1) in the pulling direction in the state where the liquid container is mounted to the container mounting part. A slanted entrance surface (22) is located at an entrance part of the guide groove, which slanted entrance surface slants so that a groove depth decreases in the movement direction of the fixing pin that relatively moves in association with an inserting operation of the liquid container into the container mounting part.