Headrest Support Device

Provided is a simple and compact headrest support device. The headrest support device () comprises a support member () coupled to a frame () of a seatback (), and a headrest pillar structure including a pillar base portion () extending laterally and supported by the support member so as to be rotatable around an axial line of the pillar base portion, and a pair of pillar main body portions () extending substantially vertically from the pillar base portion substantially in parallel to each other in a laterally spaced apart relationship and connected to a headrest (), wherein the support member is coupled to the frame at at least one coupling portion () disposed between the two pillar main body portions in front view in a headrest upright condition where the headrest is positioned above the seatback.