HEARTBEAT ga Tomaranai! (HEARTBEATが止まらないっ!; Unstoppable HEARTBEAT!) is YuiKaori's 3rd single. It was released on November 17, 2010 in 2 editions: one regular and one limited. The title track was the ending theme for the Nico Nico Douga internet series Denpa Kenkyuusha for November 2010. The coupling track, "Our Song", was used as the opening theme for YuiKaori's web radio show YuiKaori no Mi♪.
The single reached #83 on the Oricon weekly chart and charted for one week, selling 974 copies.