The effect of the Ti, Al contents on the metamorphic evolution of inclusions of Ti-Al complex oxides including TiN and MnS are investigated in common carbon steels with TiO 2 and TiN particle additions. The study is carried out based on both SEM-EDS analyses and Thermo-Calc equilibrium calculations. Moreover, the particle size distributions are investigated by using the electrolytic extraction method. Based on the results of this study, the following is suggested: (i) the steel composition is controlled to contain small amount of the Al content (<0.005 mass%) and large amount of the Ti content (>0.035 mass%) in order to obtain a high number of fine particles containing a Ti-rich oxide phase when adding TiO 2 and TiN particles; (ii) this consideration is reasonable from the view point of the agglomeration degree of different inclusion materials, which are estimated from the attractive force (van der Waals force and liquid-capillary force) and the contact angle.