Frame structure of seat

A frame structure for a seat, comprising:

• a frame including
• an upper frame section having opposite end portions and a generally channel-shaped central section, said channel-shaped section having an upper end wall portion with through-holes adapted for receipt of holders for stays of a head rest, and
• first and second side frame sections integrally connected respectively to the opposite end portions of said upper frame section;
• and
• a support bracket adapted for supporting the holders for the head rest stays, fixed to said upper frame section, said support bracket including a channel-shaped support section adapted for supporting the holders, said channel-shaped support section including a first wall portion located opposite to said upper end wall portion of said upper frame section, said first wall portion being formed with through-holes adapted for supporting the holders for the head rest stays, said through-holes of said support section being located opposite to said through-holes of said upper end wall portion of said upper frame section,
• wherein said channel-shaped section of said upper frame and said first wall portion of said channel-shaped support section form a substantially tubular structure,
• wherein said channel-shaped support section extends substantially parallel with said channel-shaped section of said upper frame, and
• wherein said support bracket has laterally extending sections, ends of said laterally extending sections being fixed respectively to said first and second side frame sections.