This headrest guide 52 for holding a pillar 43 protruding from a headrest 4 is provided with cylindrical section 61 having formed therein a through-hole 63 which extends in a longitudinal direction and into which the pillar 43 is inserted. The cylindrical section 61 has a protrusion 64 provided on the inner peripheral surface of the through-hole 63 and coming in contact with the pillar 43 inserted in the through-hole 63. The protrusion 64 extends in the longitudinal direction of the cylindrical section 61, and the length of the protrusion 64 in the top-bottom direction is set to be greater than the length thereof in the left-right or front-rear direction. The configuration makes it possible to suppress the rattling of the headrest because of an increase in the region of contact with the pillar inserted in the through-hole.