Provide a door latch apparatus with a childproof lock mechanism that is only a projecting portion of the childproof lock mechanism is movable in the release direction interlocked with an opening operation of an inside lever, so that the degree of freedom of arrangement and design of several kinds of parts assembled in a housing can be increased. A release actuating member is supported movably in an elongated guide hole of a childproof lever from a standby position to a release position. When the childproof lever is in a childproof unlocking position and when an inside lever is carried out the opening operation, a projecting portion contacts to the inside lever and moves in the opening direction, so that the release actuating member moves to the release position against a biasing unit.