The firm's April figures reveal that the DS Lite - which is still in short supply in the region - reached the landmark at the end of April, some 61 weeks since its launch. The news is particularly significant, given the fact that the PS2 took 131 weeks to achieve the same feat.
Elsewhere, the latest title in the Phoenix Wright series, Gyakuten Saiban 4, took the topspot in the monthly charts, notching up 338,000 sales. Meanwhile, the much-anticipated Super Paper Mario took the fourth place in the chart, on 240,000 sales.
In terms of hardware sales, DS Lite notched up a stonking 702,844 units, with Wii sales at 287,722 and PSP at 158,291.
Japan Hardware Sales: April
DS Lite: 702,844
DS: 2, 211
GBA SP: 3,749
GB Micro: 3,626
Xbox 360: 17,094
Source: Famitsu Marketing Data Service