To provide an alarm system and alarm device using flash light, which are able to warn even hearing impairment people of a fire break and urge them to evacuate, without causing optically-stimulated epileptic seizure.

An alarm system comprises: a relay configured to intermittently emit a fire alarm signal at a first period on the basis of a fire sensor signal; and an alarm device configured to intermittently emit flash light at a second period on the basis of the fire alarm signal. The first period is an integral multiple of the second period. The flash light emission is controlled in synchronization with the fire alarm signal with a time difference shorter than the second period.