Five guns, two of which could fire lethal bullets and a 3D printer were seized from the 27-year-old’s home, near Tokyo.
According to ANN News, Mr Imura, allegedly downloaded gun blueprints from a foreign site and then printed the resin guns with his 3D printer.
Mr Imura reportedly said he had not realized printing the guns was illegal.
Sources said the investigation was launched in February after officers were made aware of video footage of Mr Imura displaying newly printed weapons.
This is the first instance of such an arrest being made in Japan.
The world’s first 3D-printed gun was successfully fired in the US in May 2013 by a group called Defense Distributed, who made the blueprints available online.
However, the United States Department of State quickly demanded the immediate removal of the blueprints from the group’s website.
Printed gun parts were thought to have been found in the UK in October 2013, however the parts turned out to be spare components for a 3D printer.
Desktop 3D printers can be bought on the High Street for as little as £500, with more sophisticated models costing tens of thousands.