By Agence France-Presse
Tokyo has struggled to achieve the two percent inflation rate thought crucial to boosting the world's third largest economy.
The Bank of Japan last month dropped its timeframe for achieving the longstanding inflation goal.
Government data released Friday showed the core inflation rate, which excludes volatile fresh food prices, stood at 0.7 percent in April, down from 0.9 percent in the previous month.
That was slightly lower than market expectations of 0.8 percent.
With fresh food and energy stripped out, prices rose by even less -- just 0.4 percent in April, the ministry said.
The latest data comes as Japan's economy slid into reverse for the first time in two years at the beginning of the year, hit by sluggish consumption and a winter cold snap.
The economy contracted by 0.2 percent quarter-on-quarter in the January-March period, compared with growth of 0.1 percent at the end of 2017, the Cabinet Office said earlier this week.
This brought to an end a series of eight consecutive quarters of growth, a winning streak not seen since the heady days of the "miracle" boom of the 1980s when the Japanese economy ruled the world.
Japan has battled deflation for many years and the central bank's ultra-loose monetary policy appears to be having limited impact.
The Bank of Japan has signalled it has no plans to drop the policy, despite moves by other major economies.