The high-profile arrests include architect Hidetsugu Aneha, 48, who has admitted to using fake quake data for up to 100 condominiums, hotels and other buildings to cut costs, police said on Wednesday.
The case has caused outrage in Japan, one of the world's most earthquake-prone nations, and led to a series of nationally televised parliamentary hearings that detailed illegal cost-cutting in the construction business.
So far, Aneha has only been arrested on suspicion of lending his name to a designer for work that required an architectural license, a Tokyo police spokesman said.
He has already been stripped of his architectural qualifications, and his wife committed suicide last month.
Aneha, allegedly received 10 million yen ($87,000) in return for lending his name to the designer's company, Kyodo News agency reported.
Mikio Akiba, the designer, was also arrested.
Japan is hit by 20% of the
Police also arrested Moriyoshi Kimura, the president of Kimura Construction Co, and three other employees of his company in southern Japan.
Kimura Construction is suspected of submitting a falsified financial report to the land, infrastructure and transport ministry, in violation of the construction industry law, according to the spokesman.
Togo Fujita, president of eHomes Inc, a building inspection agency, and eHomes' former auditor were arrested for falsifying documents, the official said.
The official refused to give details, but Fujita is reportedly suspected of falsifying his company's financial documents in December 2001, before it acquired official certification as an inspector.
Aneha admitted during testimony in parliament in December that he had covered up potentially catastrophic defects in buildings across Japan since around 1998.
He said developers, largely Kimura Construction, asked him to cut costs by reducing the amount of steel reinforcements required by building codes.
"The government will work to revise the Building Standards Law and create other related laws as soon as possible so that an incident like this would never happen again"
Japan's chief cabinet secretary, Shinzo Abe
None of Wednesday's arrests were made on charges of data fabrication, although police hope investigations after the arrests will allow them to build a case against the suspects and other officials on charges of fabricating data, Kyodo said.
Authorities say at least 97 defective buildings linked to Aneha could collapse in a moderate tremor.
Dozens of buildings designed by Aneha, including ones in Tokyo, have been earmarked for demolition, forcing the relocation of thousands of residents.
The scandal has shocked Japan, which experiences 20% of the world's major tremors and prides itself on constructing buildings to withstand earthquakes.
The Japanese archipelago is located in an area where several continental and oceanic plates meet.
The worst earthquake in Japanese history hit the Kanto plain around Tokyo in 1923, killing more than 100,000 people.
And a 7.3 magnitude earthquake in the western city of Kobe in January 1995 killed 6,433 people.
According to government estimates, a major earthquake in Tokyo could kill 5,600 people and damage 440,000 buildings.
The government has approved 8 billion yen ($68.3 million) to compensate those who bought condominiums in faulty buildings.
The chief cabinet secretary, Shinzo Abe, said the government would push ahead with its proposed revision of the architectural law to ensure such a scandal does not recur.
"The government will do its best to ensure the residents' safety," he said.
"The government will work to revise the Building Standards Law and create other related laws as soon as possible so that an incident like this would never happen again," he added.