Developers often refactor source code to improve its quality during software development. A challenge in refactoring is to determine if it can be applied or not. To help with this decision-making process, we aim to search for past refactoring cases that are similar to the current refactoring scenario. We have designed and implemented a system called RefSearch that enables users to search for refactoring cases through a user-friendly query language. The system collects refactoring instances using two refactoring detectors and provides a web interface for querying and browsing the cases. We used four refactoring scenarios as test cases to evaluate the expressiveness of the query language and the search performance of the system. RefSearch is available at https://github.com/salab/refsearch.