Numerous products are on the market every day and consumption is becoming increasingly polarized. Some products have been introduced to the market for the first time and others are the existing products that have upgraded performance. For companies, new products must be released constantly to prevent losing existing customers and to increase loyalty. However, when companies released new product, they communicate consumer brand name and core benefits of the new product. Moreover, if a new product fails, the amount that the company has to pay is bound to grow. So companies often use brand extension strategies that use the names of famous brands that are already loved by their customers for new products. In this study, the effect of extension similarity, time of release, and message type on brand extension was investigated. Result shows that using abstract messages rather than specific messages is more effective when similarities with existing brands are poor. In particular, the closer the release period is, the more effective these effects are. However, in case of extending the brand with high similarity products, it is effective to focus on concrete messages when the release time is near, and to communicate abstract messages when the release time is long. This result suggests that companies should take into consideration not only the similarity of extension but also the timing and characteristics of messages when extending the brand.