In a pocket coil spring structure assembling apparatus, a row-of-pocket-coil-springs auxiliary feed stock mechanism and a row-of-pocket-coil-springs delivery mechanism are connected together in series so as to form a row-of-pocket-coil-springs supply unit, a plurality of row-of-pocket-coil-springs supply units are disposed on an upstream side with respect to a sealing/cutting mechanism, a control apparatus is allowed to alternatively select a row-of-pocket-coil-springs supply unit to face the sealing/cutting mechanism from the plurality of row-of-pocket-coil-springs supply units, and a row-of-pocket-coil-springs supply unit alternatively selected is moved to face the sealing/cutting mechanism.