Officials said search teams are scouring a ravine near where the plane's scattered wreckage was found. They're hoping the recorder will provide answers about why the plane crashed.
The Sukhoi Superjet-100 slammed into Mount Salak last Wednesday during a flight intended to woo potential buyers in the fast-expanding domestic airlines industry in Indonesia.
All 45 people on board are presumed dead. Helicopters have been ferrying remains to Jakarta, the capital, for identification since Saturday.
It's unclear what caused the crash about halfway through the 50-minute flight, so finding the "black box" recorder is a priority.
The Associated Press contributed to this report.