Open innovation is emerging as an important issue as the economic situation and consumer needs change dynamically. However, prior studies have examined the relationship between open innovation activities and innovation performance without distinguishing between incremental innovation and radical innovation which have completely different characteristics. Moreover, technology sourcing is considered to be one of the main factors affecting innovation performance, but it has been rarely studied in open innovation research. Therefore, I examined the relationship between open innovation activities and incremental and radical innovation. I found that external knowledge scanning, internal knowledge sharing and technology sourcing significantly and positively affect incremental innovation. Especially, the results showed that technology sourcing, unlike the other two factors, is the only positive and significant impact element to radical innovation.