The Covid-19 pandemic has caused the biggest humanitarian crisis of the 21st century. In an overpopulated country like Bangladesh, it is even tougher to fight the situation. The government and different stakeholders are relentlessly encouraging people to maintain the necessary health care measures where the mass media is playing the supporting role. The research examines how mass media has been influencing in the behavioral change during this pandemic and played the role of "changing agent". The research is designed on mixed method, including content analysis and survey. This study analyses 191 health awareness-based news from three different print newspapers and two television channels' prime hour bulletins within the timeline of 1st March to 31st March. Also, a survey questionnaire was set with close-ended questions to accumulate people's feedback. Using the "The Behaviorism Theory", this study explains, how all behaviors are acquired through conditioning. Throughout this theoretical lens, this research finds out how media worked as an external stimulus in changing people's behavior pattern.