Construction workers moved fast to fill the hole, which spanned a five-lane street, stretching 30 metres (98 feet) wide and 15 metres deep.
The chasm first  appeared on Tuesday, 8 November, in a business district of the south-west city of Fukuoka.
No one was hurt in the collapse, but local media reported disruptions to electricity, gas and water services.
The street reopened at 05:00 Tuesday (20:00 GMT Monday), in time for rush hour.
The city's Mayor Soichiro Takashima released a statement apologising for the "great trouble", thanking workers for their efforts, and insisting that an investigation into the incident's causes would continue.
City officials have said it could have been caused by underground construction nearby.
A busy Japanese road reopened on Tuesday, just one week after it was wrecked by a gigantic sinkhole.