Provided is a headrest device configured so that rattling can be reduced. This headrest device (10) is configured such that: a connection section (21, 23) is constituted of an inner gear (25a, 25b) and an outer gear (27a, 27b), which mesh with each other on an axis (X1, X2) the pitch of inner tooth sections (26a, 26b) and the pitch of outer tooth sections (31a, 31b) are set to be smaller on the left side of the axis (X1, X2) than on the right side thereof a backrest-side engagement support section (12) and the lower side of an arm section (19) are connected by a backrest-side connection section (21) the upper side of the arm section (19) and a headrest-side engagement support section (16) are connected by a headrest-side connection section (23) and a pressing operation section (33) of an operation section (32) is disposed at a distance from the axis (X1, X2), the operation section (32) being used to select: a locked state in which the inner gear (25a, 25b) and the outer gear (27a, 27b) are engaged with each other to retain a headrest and an unlocked state in which the inner gear (25a, 25b) and the outer gear (27a, 27b) are separated from each other to allow the headrest to be operated.提供一種能夠減輕搖晃的頭靠裝置。由在各軸(X1、X2)上而相咬合之內齒輪(25a、b)和外齒輪(27a、b),來構成各連結部(21、23),在內齒部(26a、b)之間隔以及外齒部(31a、b)之間隔處,將各軸(X1、X2)上之左方側形成為較右方側而更狹窄。將背靠側卡合支持部(12)和臂部(19)之下方側之間,藉由背靠側連結部(21)來作連結,將臂部(19)之上方側和頭靠側卡合支持部(16),藉由頭靠側連結部(23)來作連結,將用以對於鎖死狀態和解除狀態作選擇之操作部(32)中的推壓操作部(33),從各軸(X1、X2)上而分離地來作配置,而構成頭靠裝置(10),其中,該鎖死狀態,係使內齒輪(25a、b)和外齒輪(27a、b)作卡合而使頭靠部停止,該解除狀態,係使內齒輪(25a、b)和外齒輪(27a、b)相分離而使頭靠部動作。11‧‧‧支持本體部12‧‧‧背靠側卡合支持部13‧‧‧背靠側支持用內齒輪14‧‧‧背靠側環狀支持部15‧‧‧支持板部16‧‧‧頭靠側卡合支持部17‧‧‧頭靠側支持用內齒輪18‧‧‧頭靠側環狀支持部19‧‧‧臂部21‧‧‧背靠側連結部23‧‧‧頭靠側連結部25a、25b‧‧‧內齒輪(第1齒輪、第2齒輪)26a、26b‧‧‧內齒部(第1齒部、第2齒部)27a、27b‧‧‧外齒輪(第1齒輪、第2齒輪)28a、28b‧‧‧支持用外齒部29a、29b‧‧‧卡合用外齒部30a、30b‧‧‧軸狀部31a、31b‧‧‧外齒部(第1齒部、第2齒部)32‧‧‧操作部33‧‧‧操作按壓部34‧‧‧背靠側按壓部35‧‧‧頭靠側按壓部36a、36b‧‧‧彈性構件37a、37b‧‧‧連結軸構件X1‧‧‧背靠側軸(背靠側連結部之軸)X2‧‧‧頭靠側軸(頭靠側連結部之軸)
