Adjustable headrest

An adjustable headrest comprising:

• a stay member extending upward from a seat back of a vehicle seat;
• a main body for supporting a head portion of an occupant on the seat from rear, the main body including a frame rotatably connected to the stay member;
• a ratchet mechanism arranged in the main body, the ratchet mechanism including a base plate fixed to the frame, a ratchet plate with a pawl portion, a support pin connecting the ratchet plate with the base plate, and a lock member fixed to the frame, the base plate having a receiving hole into which the support pin is inserted, the lock member having lock teeth engageable with the pawl portion in different positions, an inclination of the main body relative to the stay member changed according to the position of an engagement between the pawl portion and the lock teeth, the engagement between the pawl portion and the lock teeth preventing the main body from inclining backward relative to the stay member;
• and
• an impact absorbing slit formed in the base plate, the slit having a width smaller than an outside diameter of the support pin and extending backward from the receiving hole, wherein when the head portion receives an impact in a backward direction and the main body is intensely pressed backward, the support pin moves in the slit while widening the width with pressure and the main body moves backward so that deformation of the slit accompanied with movement of the support pin absorbs the impact.