Disclosed is a fire detector and a fire warning method. The fire detector includes: a fire sensor detecting a factor corresponding to fire; and a controller determining whether a fire has occurred, by using a sensed value of the fire sensor, and determining whether a reset event is generated, through an on/off state of the lamp. The fire warning method includes: performing, by a controller, monitoring for a fire; determining, by the controller, whether a fire has occurred; and giving a warning when it is determined that a fire has occurred, and simultaneously determining whether a reset event is generated, through an on/off state of a lamp.