| Masahiro Sekiguchi 関口 正大 | |
| Birth Date: | 21 April 1998 |
| Birth Place: | Niigata, Niigata, Japan |
| Height: | 1.72 m |
| Currentclub: | Ventforet Kofu |
| Clubnumber: | 23 |
| Position: | Right-back |
| Youthyears1: | 2004–2010 |
| Youthclubs1: | Club F3 |
| Youthyears2: | 2011–2013 |
| Youthclubs2: | FC Ikarashi |
| Youthyears3: | 2014–2016 |
| Youthclubs3: | Niigata Meikun High School |
| Collegeyears1: | 2017–2020 |
| College1: | Hosei University |
| Years1: | 2020– |
| Clubs1: | Ventforet Kofu |
| Caps1: | 126 |
| Goals1: | 4 |
| Club-Update: | 21:56, 13 June 2024 (UTC) |
is a Japanese footballer currently playing as a right-back for club Ventforet Kofu.
| Club | Season | League | National Cup | League Cup | Other | Total | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Division | Apps | Goals | Apps | Goals | Apps | Goals | Apps | Goals | Apps | Goals | |||
| Japan | League | Emperor's Cup | J. League Cup | Other | Total | ||||||||
| Hosei University | 2019 | – | 4 | 0 | – | – | 4 | 0 | |||||
| Ventforet Kofu | 2020 | J2 League | 2 | 0 | 0 | 0 | – | – | 2 | 0 | |||
| 2021 | J2 League | 34 | 2 | 0 | 0 | – | – | 34 | 2 | ||||
| 2022 | J2 League | 37 | 0 | 4 | 0 | – | – | 41 | 0 | ||||
| 2023 | J2 League | 34 | 1 | 2 | 0 | – | 6 | 1 | 42 | 2 | |||
| 2024 | J2 League | 19 | 1 | 1 | 0 | 0 | 0 | 2 | 0 | 22 | 1 | ||
| Total | 126 | 4 | 7 | 0 | 0 | 0 | 8 | 1 | 141 | 5 | |||
| Career total | 126 | 4 | 11 | 0 | 0 | 0 | 8 | 1 | 145 | 5 | |||
Ventforet Kofu