Junichi Usui (臼井 淳一 Usui Jun'ichi) (born October 6, 1957 in Miyagi) is a retired Japanese long jumper, best known for finishing seventh at the 1984 Olympic Games.
| Year | Competition | Venue | Position | Notes |
|---|---|---|---|---|
| Representing Japan | ||||
| 1978 | Asian Games | Bangkok, Thailand | 2nd | |
| 1979 | Asian Championships | Tokyo, Japan | 1st | 7.97m CR |
| 1981 | Asian Championships | Tokyo, Japan | 2nd | |
| 1982 | Asian Games | New Delhi, India | 3rd | |
| 1984 | Olympic Games | Los Angeles, United States | 7th | |
| 1985 | Asian Championships | Jakarta, Indonesia | 3rd | |
| 1986 | Asian Games | Seoul, South Korea | 2nd | |
| 1987 | World Championships | Rome, Italy | 12th | |
| 1988 | Olympic Games | Seoul, South Korea | NM | |