The signal processing apparatus inserts the header information in a frame to probably be the reproduction start point by including: the first and the second coding units that code an input signal per frame; the first header inserting unit that inserts the SBR header indicating management information of the coded signal represented by a sequence of frames, in each frame at a regular interval within the coded signal; the control unit that determines a frame in which the SBR header is inserted, independent of the frames in which the first header inserting unit inserts the SBR header; and the second header inserting unit that singly inserts the SBR header in the frame determined by the control unit.