Japan's jobless rate edged up to 4.6 percent in December from 4.5 percent in the previous month, the government said on Tuesday.
Economists had forecast the figure would stay flat at 4.5 percent.
The total number of jobless stood at 2.75 million, a drop of 240,000 on the previous year, figures from the Ministry of Internal Affairs and Communication showed.
But as Japan's working-age population is also falling that still meant the unemployment rate went up.
The labour ministry said in a separate survey that the ratio of job offers to job seekers was 0.71 in December, up from 0.69 in November, meaning there were 71 job offers to every 100 job hunters.