First click on the video on facebook.com you want to download, then copy video link (For eg. https://www.facebook.com/fanTomOrJerry/videos/709099496689620) then select the quality of video you want to download in and you will be redirected to Facebook's CDN for download where you need to click on 3 dot menu and click on download.
This tool may not work in future and may be removed because of Facebook constantly updating their API's.
Note: This website does not host any pirated or copyright content on its server, and all
the videos that you download are downloaded to your system directly from their respective CDN servers.