Because licensing an open source software (OSS) product restricts its reuse, the developer of the product has to consider the impact on reuse when choosing the license. However, to the best of our knowledge, there are no quantitative studies on the impact of software licenses on software reuse. To identify the impact, this paper presents a quantitative investigation into the relationship between the software license and copy-and-paste reuse on actual OSS products. The results show that the license of a product affects the frequency of reuse. On the other hand, copy-and-paste reuse occurs mostly in the source files distributed under the same license.