Health Ministry officials estimate that about 600,000 couples tied the knot in 2017 in Japan, the fewest since the end of World War Two.
They say the figure is down by about 13,000 compared to 2016 and marks the fifth-straight year it has declined.
Officials believe that a decrease in the population of young people is a major factor.
Last year, 212,000 couples filed for divorce, the fewest in 20 years.
Calculations show that a couple married every 52 seconds while a couple divorced every 2 minutes and 29 seconds.
The officials say Japan needs to find ways to stop the declining population and help more young people get married.