1. A door opener-closer, comprising:
a door handle;
a flexible antenna including a magnetic body core made of a soft magnetic body, received in the door handle and serving as a transmitter-receiver communicating with a portable device;
a handle body having a backface side formed with a cover receiver;
a cover handle united with the antenna and made of a plastic resin, the cover handle mating with the cover receiver in such a manner as to be held by the cover receiver; and
a sensor for sensing at least one of the followings which are implemented by an operator carrying the portable device:
approaching a door,
contacting the door, and
operating the door,
to thereby allow the transmitter-receiver and the portable device to communicate with each other, thus locking or unlocking the door.