Recently, sentiment analysis is actively researched in the field of natural language processing because of the expansion of computer science and social media. However, sentiment analysis has a wide range of applications and it might be challenging for individual researchers to review and comprehend the trends of the studies. Therefore, this study suggests trends in sentiment analysis research to help sentiment analysis researchers. The sources of data collection are Google Scholar and Scopus. As a result, studies using various modalities, researching the change from a particular event and based on language itself have been explored actively in recent years.