It was released by Avex Trax on March 17, 2004, serving as the lead single to Amuro's seventh studio album Queen of Hip-Pop (2005).

The B-side "Strobe" was first planned as the main track of this single and when Amuro got the demo for "Alarm" the song was titled "Clock."

Since its release, "Alarm" has appeared on several of Amuro's concert tours, as well as her greatest hits album Best Fiction (2008).

[13] The video was predominately filmed in black-and-white and depicts Amuro and her backup dancers dancing in a warehouse wearing biker fashion.

There are also interspersed scenes throughout the video of a TV screen in a bar showing Amuro walking down a runway while wearing a yellow minidress.

At the end of the video, a ring is chucked at the screen and picked up by a long-haired man whose look is reminiscent of Amuro’s ex-husband.

CDJournal praised the track for being simple, with as few notes as possible, and the sharpness of the music is being enhanced, bringing her vocals to the fore.

[9] Its appearance on Queen of Hip-Pop was praised for the matte and sexy singing voice combined with the heavy bass that makes the listener's heart pound with excitement.

[8] For Best Fiction, the song was praised for its cool, solid bass and a stoic development that doesn't miss a beat.