Technology development has made automation process simpler. The rise in population in the country increases demand for electrical knowledge, Security personnel and more application of electricity in their lives for better improvement and efficient services in homes and the country at large. The need of security is essential to human and living creatures. Considering the need of security we realized that the level of crimes such as theft is increasing, which causes poverty to low class people and class beings. Security is a vital tool in life as it helps people comfortably do business, live well hence encouraging investment the act of employing people to keep monitoring the area is expensive, Therefore a unit need to be designed to solve this problem. In considering the need of many I care up with infrared Based Security Alarm system which alerts one when the intruder interference with IR. i.e. when someone enters in a given area it turns on the security lamps and hence the Buzzer/ac alarm using Relay can produce sound hence detection at the intruder. Infrared based security alarm circuit an detect any movement trigger the alarm. THIS circuit is very useful in homes, banks, shops restricted areas where an alert alarm is needed on any movement. This circuit is based on IR sensor where an infrared beam is continuously falling on a photodiode and whenever this infrared beam breaks by any kind of movement alarm is triggered. Infrared sensor consist an infrared LED and photodiode in which IR LED emits infrared radiation and photodiode detects the radiation photodiode conducts current in reverse direction whenever light falls on it and voltages across it changes this voltages charge is sensed by voltages comparator i.e.(LM358) and generates output accordingly. In this infrared based security alarm circuit we have placed infrared LED in front of photodiode so that IR light can directly falls in photodiode. Whenever someone moves through this beam IR rays stop falling on photodiode and Buzzer start beeping . Buzzer automatically stops after sometimes as buzzer is connected to 55 timer in mono stable mode. OBJECTIVE Main objectives To design infrared based security alarm.