Previous researches on advertising type of extension product have limitations in focusing on adult and simplifying advertising type of extension product as elaborational/relational ad. This study expands to children and subdivides advertising type of extension product by elaborational/ relational/elaborational-relational ad. Based on these experimental setting, this study investigates the effects of interaction between age and advertising type in incongruent brand extension. The results show that adult's evaluation on incongruent extension product is the most favorable in elaborational-relational ad. On the other hand, children's evaluation on incongruent extension product is the most favorable in elaborational ad. Based on these findings, theoretical and practical implication and future direction are discussed.