This study analyzed the effect of the sensitivity of news related to onions on producers' decision-making on cultivation areas and market supply and demand. We collected onion-related article data and derived the sentiment index through sentiment analysis using neural network-based learning. We estimated the cultivation area function, including the sentiment index we made. We analyzed the impact of news sensitivity on the onion market by constructing an onion market supply and demand model. Then, we gave a sentiment index shock to the cultivation area to examine the impact on the onion market. We also explored the sensitivity analysis to emphasize the news in June, July, and August plays an important role in the supply side. To the best of our knowledge, our approach using sentiment index in the agricultural model is the first trial. Therefore, our study can introduce an approach to improve the accuracy of modeling for agriculture and apply it to the area of agricultural economics.