In influencer marketing, influencers are usually selected based on the number of followers. But is this the right selection method? In this study, we conducted a preliminary survey of SDG-related words on Instagram. Among accounts with posts that included hashtags “#food loss” and “#renewable energy,” we selected one account with a high view count for each hashtag. Then, for these two accounts, we conducted a network analysis using mutual following relationships as ties and accounts as nodes. We found that the former account had a broadcasting-type network, whereas the latter account had a community-type network. In a community type network, users are very like-minded, and influencers with community-type networks are considered more effective at the purchase decision stage. Owing to a higher rate and number of comments for the community-type network, these two values could be used as substitute indicators for network structure.