We discuss the melt-mixing characteristics of different geometries of pitched-tip kneading disks (ptKD). Extrusion experiment was performed under the fully-filled state in the kneading zone by controlling the fill lengths for different KDs. We study the variation of the particle size distribution and the rheological response of ABS (acrylonitrile-butadiene-styrene copolymer) caused by melt-mixing. We found that the increase or decrease of the fine and coarse particles depends on the type of KD. Furthermore, the change of the particle size distribution affects the storage modulus at low frequencies. From these results, different mixing characteristics of different KDs are evaluated.