Aggregation structure of (hyperbranched polystyrene/linear polystyrene) blend films was examined by dynamic secondary ion mass spectroscopy (DSMS) and neutron refflectivity (NR). Two types of monodisperse hyperbranched polystyrenes (HB-PS) with longer and shorter branches were synthesized combing cationic and anionic polymerizations. Total molecular mass for the both was fixed to be 1M. Deuterated polystyrene (dPS) with molecular weight of 1M was used as a linear component. DSMS and NR measurements revealed that HB-PS are preferentially segregated at both surface and substrate interface. Interestingly, to what extent HB-PS exists at the surface and interface was dependent on the architecture of HB-PS. This might be explained in terms of number density of chain ends and distorted chain conformation. The above results were in good accordance with a prediction based on simulation using a self-consistent filed theory. Finally, a possibility of HB-PS as a surface or interfacial modifier is discussed.