|Anime||Episode 9 (Flashback)|
Jun had short dark brown hair and dark brown eyes. He was seen wearing the standard male school uniform.
On the school trip in 1983, Matsunaga's class had visited the Yomiyama Shrine. He was the first death that took place that day. After praying at the shrine, Class 3's teacher, Mr. Koga declared everything would be okay and the class is free from the curse. After leaving, the sky turned overcast, and it began to rain. Everyone left the shrine and Matsunaga was walking behind Hamaguchi. Hamaguchi, claimed to have been dumber than most, was the only one who brought an umbrella in the lightning storm, and the lightning struck him, killing him instantly. When Matsunaga opened his eyes, he said that he could smell Hamaguchi's flesh burning.
- His death caused several students to flee in terror; which, in turn, caused Yuki Hoshikawa's death.
- He is one of two students whose death involves an umbrella (the other being Yukari).