Tokyo put spy satellites into operation in the 2000s after North Korea fired a mid-range ballistic missile over the Japanese mainland and into the western Pacific in 1998.
The Japan Aerospace Exploration Agency (JAXA) and Mitsubishi Heavy Industries launched the H-2A rocket from Tanegashima Space Center in southwestern Japan, the agency said.
The launch at 10:21 am (0121 GMT) went smoothly, a JAXA spokeswoman said, noting "the satellite separated and entered orbit as scheduled."
Five Japanese intelligence satellites are currently in orbit -- two optical satellites and three radar satellites, including a backup radar satellite launched last month, AFP reported.
The new satellite will succeed one of the two optical satellites that was launched in 2009, a Cabinet Office official said.