The objectives of this study are to investigate the basic fluid characteristics for spout-fluid beds of binary mixtures of particles, and to compare the hydrodynamics with that of coarse particles only. As results, two patterns of flow in spout-fluid beds, that is, spouting with aeration (SA) and spouting with fluidization (SF), were mapped as the regions depending on the relative values of the central and auxiliary gas flow rates. The operation regions for SA were reduced by the increase of the ratio of fine particles. Also, a correlation for predicting the minimum SF velocity was presented. It was found that the overall bed pressure drop under minimum SA condition increased linearly and also the gas velocity through the annulus increased, as the proportion of the auxiliary flow rate to a fixed total gas flow rate was increased for operation in the SA region of binary mixtures. The values as described above were smaller than those in the case of using coarse particles only. Moreover, the particle circulation rate increased and also both the average spout diameter and the fountain height decreased, as the proportion of the auxiliary flow rate to a fixed total gas flow rate was increased.