The governing body of Japan's tradition-steeped sport of sumo replaced its leader on Thursday amid a widening gambling scandal linked to organised crime.
Musashigawa resigned as chairman of the Japan Sumo Association, citing poor health, at an extraordinary board meeting which elected Hanaregoma as his replacement, the association said.
Musashigawa, 62, whose real name is Goro Ishiyama, underwent stomach cancer surgery in July and returned to the job last week.
"I feel at a loss as I was appointed at this very difficult time," Hanaregoma, also 62, whose real name is Teruyuki Nishimori, told a news conference.
Musashigawa assumed the post in September 2008 to take over from Kitanoumi in the middle of a scandal involving sumo wrestlers suspected of smoking marijuana.
The image of sumo has been tarnished in recent years by revelations of drug use, claims of match-fixing and the 2007 death of a trainee who had been the victim of a brutal "hazing" by his stable mates.
Earlier this month, three gangsters and a former sumo wrestler were arrested on suspicion they extorted Y6 million ($A80,000) from a broker of illegal baseball gambling.
Sumo's governing body has said at least 27 wrestlers, masters and others from 13 sumo training centres or "stables" have admitted to illegally gambling on the results of Japanese professional baseball games.
Betting in Japan is permitted only on horse racing and certain motor sports.