Influence of Fit between Parent Product and Extension Product, The purpose of this study is to examine the influence of fit(high vs. low), advertising type of extension product(relational ad vs. elaborational ad), and parent brand's market position(market leader vs. market follower) on the evaluation toward extension product. Especially, this study focus on the moderating role of parent brand's market position which has never been considered in previous studies. The results are as follows. If the parent brand is a market leader, the consumer's evaluation toward extension product is more positive after relational ad when fit of brand extension is high, whereas such evaluation is more positive after elaborational ad when fit of brand extension is low. However if the parent brand is a market follower, the consumer's evaluation toward extension product, although not statistically significant, is more positive after elaborational ad irrespective of fit of brand extension. This study suggests that there is a need to consider the characteristics variables of parent brand such as parent brand's market position as well as consumer characteristics variables as a moderating variable in order to develop an effective advertising strategy on extension product.