The suspect, Yoshitomo Imura, an employee at a college, kept the plastic guns at his home in Kawasaki, Kanagawa Prefecture, in mid-April, the police said, adding that no bullets for the guns have been found.
This is the first time Japan's firearm control law has been applied for the possession of guns produced by a three-dimensional printer, Kyodo news reported.
Police had launched an investigation after Imura posted a video footage on the Internet of the guns, which he claimed to have produced himself, along with blueprints for them earlier this year.
"I produced the guns, but I didn't think it was illegal. I can't complain about the arrest if the police regard them as real guns," Imura, who purchased a 3-D printer at around 60,000 yen (USD 590 approx) through the Internet, was quoted as telling investigators during the search.
More From This Section
They believe Imura downloaded blueprints for producing guns by 3-D printers from websites hosted overseas, which could constitute a violation of a law banning the production of firearms.
It is expected that 3-D printers will contribute to cutting the cost of producing auto and home electronics parts. But they also enable easy creation of firearms, with a US gun maker announcing last year it succeeded in firing real bullets using a gun produced by a 3-D printer.
Weapons assembled from parts produced by the printers are not detectable with regular security equipment, like that found at airports, leading to fears that they may be used in hijackings.
Security authorities around the world are on alert as data for creating guns using the printers are easily accessible on the Internet and the guns cannot be detected by metal detectors if they are made of resin.