Medical attendants rushed onto the platform in Kyoto on Wednesday when Maizuru Mayor Ryozo Tatami, 67, tumbled to the floor while making a speech, the Mainichi reports.
Sumo wrestling is facing another scandal as female medics were asked to stop attending to a stricken official because of ancient law banning "impure" women from entering the "sacred" ring. The mayor was taken to a hospital and is said to be in a stable condition.
Sumo chief Nobuyoshi Hakkaku called the announcement inappropriate and apologized late Wednesday, while thanking the women for working to save the mayor.
In February, a sumo wrestler was arrested on suspicion of indecent assault, and last month, Egyptian sumo wrestler Osunaarashi was arrested for allegedly driving without a licence when he got into a vehicle accident in central Japan.
"The referee was upset and made the announcement, but it was an inappropriate response because the situation could have been life-threatening", Hakkaku said in the statement.
The actions of the judge drew criticism from television commentators and on social media in Japan.
"Of course it is important to protect tradition, but the way it excludes women perhaps is out of step with the times, and that's how I feel as a woman", said Yurika Mita, a newscaster on a Fuji Television Network talk show.
More medics, including at least three women, entered the ring to assist in the life-saving efforts. One of the traditional responsibilities of the governor of Osaka is to crown the champion of an annual sumo tournament, so she would always need to request permission to enter the ring in order to fulfill that duty.
The tradition drew public attention for the first time in 1978, when a 10-year-old girl advanced to the final round of a children's sumo championship.