Social media is being used as an effective marketing tool for companies by providing a new way for brands to interact with their audience. As the importance of social media increases, the effects of social media on marketing performance such as awareness, sales, and corporate value are being studied. However, the effect of social media on corporate performance has not been well researched. The research on firm performance is limited in that it only explains the financial investment side of the company such as volatility of stock price and does not fully explain the corporate performance of the consumer side. In addition, social media is providing new opportunities and benefits to brand management, but it is difficult to measure how social media marketing contributes to brand success. In this context, this study analyzes the mediating role of brand equity in the relationship between eWOM volume of social media and firm performance, and analyzes how the effect of brand equity depends on the type of corporate(product/service). The results showed that the eWOM volume of social media had a positive effect on firm performance through brand equity, and this relationship was strengthened in service firms as compared to product firms.