Phase separation induced by a two-step temperature jump was studied by time-resolved light scattering and scanning electron microscopy for polystyrene/poly(2-chlorostyrene) blends. A co-continuous domain structure was formed by the first-step jump, with small droplets being formed in these co-continuous domains by the second-step jump made in the intermediate stage, as well as in the late stage, of phase separation at the first-step temperature. When the duration of the first step was long enough, the growth of co-continuous domains formed after the second jump was well described by the same power function as that found for the corresponding single-step jump if the phase-separation time was shifted; this feature was confirmed for different first-step temperatures.