Headrest of automobile seat

A headrest of an automobile seat has a function of supporting the neck and comprises a headrest part and a neck supporting part. The top of a headrest frame is embedded in the headrest part, an adjusting guide pipe and a locking rod are fixed with the headrest part, a part of a neck supporting frame is embedded in the neck supporting part, an end of the neck supporting frame is inserted into the adjusting guide pipe, the locking rod is provided with a lock bolt, the neck supporting frame is provided with a plurality of lock holes, and the lock bolt is combined with different lock holes selectively to extend out of the neck supporting part in adjustable mode. A compressed spring is placed between an unlock button and one end face of the locking rod, the locking rod, the unlock button and the spring are supported by a sleeve fixed on the headrest frame, and the lock bolt and the lock holes form a one-way combining mechanism.