일본 인구 감소 시뮬레이터

Ehime愛媛県

Seiyo 西予市

Data last updated:

Seiyo, Ehime, Japan has a population of 31,628 (2025 national census). IPSS projections estimate 28,848 by 2030 and 18,200 by 2050 (a decrease of about 48.6% from 2020), with the share of residents aged 65+ rising from 44.1% in 2020 to 54.0%.Sources: Japan Census (Statistics Bureau), IPSS Regional Population Projections (2023)

2025년

(실적)

31,628명

2030년

(추계)

28,848명

▼ -18.5%

2040년

(추계)

23,128명

▼ -34.6%

2050년

(추계)

18,200명

▼ -48.6%

Change vs. 2020 census

고령화율(65세 이상): 2020년 44.1%→2050년 54%

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Ehime (愛媛県)의 다른 시구정촌

데이터 출처

  • 일본 정부 통계 종합 포털(e-Stat)(https://www.e-stat.go.jp/)
  • 국립사회보장・인구문제연구소 「일본의 지역별 장래추계인구(레이와 5년 추계)」

※이 서비스는 e-Stat의 API 기능을 사용하고 있으나 서비스 내용은 일본 정부에 의해 보증된 것이 아닙니다.

Seiyo Population Table (1980–2050)

Population by year: national census results (restated to current municipal boundaries) and IPSS (2023) projections based on the 2020 census.

YearPopulationvs 2020Type
198056,175▲ +58.7%Census
198554,804▲ +54.9%Census
199051,893▲ +46.6%Census
199549,022▲ +38.5%Census
200047,217▲ +33.4%Census
200544,948▲ +27.0%Census
201042,080▲ +18.9%Census
201538,919▲ +10.0%Census
202035,388—Census
202531,628▼ -10.6%Census
203028,848▼ -18.5%Projection
203525,881▼ -26.9%Projection
204023,128▼ -34.6%Projection
204520,560▼ -41.9%Projection
205018,200▼ -48.6%Projection

About Seiyo

Overview

Seiyo (西予市) is a municipality in Ehime, Japan, with a population of 31,628 as of 2025.

Population Projection of Seiyo

According to projections by Japan's National Institute of Population and Social Security Research (IPSS), Seiyo's population is expected to reach 28,848 by 2030 (-18.5%), 23,128 by 2040 (-34.6%), and 18,200 by 2050 (-48.6%). A significant population decline is projected over the next three decades.

Aging Rate of Seiyo

The aging rate (percentage of residents aged 65 and over) is 44.1% as of 2020 and is projected to rise to 54.0% by 2050. More than half of residents will be seniors, placing the town in the "marginal municipality" category.

National Comparison

Seiyo is experiencing one of the faster rates of population decline in Japan.

National and Prefectural Rank

  • Population decline rate: Ranked #392 out of 1903 municipalities nationwide.
  • Aging rate in 2050: Ranked #328 out of 1903 nationwide.
  • Population size: Ranked #872 out of 1917 nationwide.
  • Related: National rankings / All municipalities in Ehime

Ehime (愛媛県)의 소득 수준: Ehime (愛媛県)의 평균 연봉(연령·성별·기업 규모별)jpsalary / 후생노동성 임금구조 기본통계조사

Frequently Asked Questions

Q.What is the current population of Seiyo, Ehime?
A.According to the 2025 national census, Seiyo has a population of 31,628.
Q.What is the population of Seiyo in 2026?
A.Seiyo's population in 2026 is estimated at approximately 31,072. This is an interpolated reference value between the 2025 census (31,628) and the IPSS projection for 2030 (28,848).
Q.What is the projected population of Seiyo in the future?
A.According to IPSS projections, Seiyo's population is expected to be 28,848 in 2030, 23,128 in 2040, and 18,200 in 2050.
Q.What is the population decline rate of Seiyo?
A.Over the 30 years from 2020 to 2050, Seiyo's population is projected to change by -48.6%. The 10-year change is -18.5% and the 20-year change is -34.6%.
Q.Why is the population of Seiyo declining?
A.Nationwide, Japan's population decline is driven by natural decrease (deaths exceeding births) and, in regional municipalities, by net out-migration of young people to major metropolitan areas. In Seiyo, the share of residents aged 65+ is projected to rise from 44.1% to 54.0% by 2050, which further accelerates natural decrease.
Q.What is the aging rate of Seiyo?
A.Seiyo's aging rate (percentage aged 65 and over) is 44.1% as of 2020, projected to rise to 54.0% by 2050.
Q.Where does this population data come from?
A.Historical data is sourced from Japan's national census via the e-Stat API (Statistics Bureau of Japan). Future projections are from the National Institute of Population and Social Security Research (IPSS) "Regional Population Projections 2023".
Q.Is the data up to date?
A.Historical data uses national census results through 2025. Future projections use the IPSS 2023 edition, which is based on the 2020 census.

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