An alarm clock includes a power supply unit; a key input setting unit (110); the lamp (140); a microcomputer (120) configured to be provided with a timer having a clock function; the time display unit (170); the alarm module (160) configured to be selectively turned on and off in response to the alarm control signal output by the microcomputer (120); a lamp power supply control unit (130) configured to be selectively switched on and off in response to the lamp drive control signal output by the microcomputer (120); and a lamp current adjustment unit (160) configured to perform control so that an amount of current flowing through the lamp (140) gradually increases based on the pulse width signal output by the microcomputer (120). The lamp gradually fades in and an alarm is issued after the lamp has been completely lit up.