An apparatus for automatically locking ship containers. The apparatus has a housing having a pair of housing halves which are symmetrical to each other, an operating element having a pair of operating element halves which are symmetrical to each other and assembled with each other in the housing, and upper and lower lockers which are assembled with each other in the operating element. By operating the upper and lower lockers using a weight of a container, it is possible to lock and unlock containers loaded on a ship to and from each other.