To provide a door for automobile with improved occupant protection performance against a collision force from the front of the automobile, and a door locking part capable of surely releasing the lock even after the door receives a collision force.

The door 10 for an automobile has a door frame openably/ closably mounted to a vehicle body 31 by a hinge 32, and the door locking part 35 locks to keep the door closed. A door beam 70 bridges between a part where the hinge 32 is attached and a part where the door locking part 35 is attached on the door frame. The door beam 70 has a first segment 71 and a second segment 72 which are aligned, the ends of each of the segments 71b and 72a overlapping in the vehicle width direction. The ends 71b and 72a are bolted together to relatively move only the prescribed distance when a fixed or a greater compression force is applied to the door beam 70.