Test coverage describes the degree to which the source code of a program has been tested. While test coverage is increased temporarily by writing tests, coverage tends to drop gradually if the tests are not enough maintained continuously. However, it is annoying to manually find code no longer tested. We present ``concov'', continuous test coverage viewer, which allows us to comprehend continuous changes of coverage by using continuous integration. Concov helps us find coverage-degraded points and raises developpers' awareness of the software testing.