Their identities were not disclosed, and no details were provided on where and how the executions took place.
The suspects, the ministry said, were identified late last year in an interior ministry probe into wildfires in the provinces of Latakia, Tartus and Homs.
"They confessed that they had started fires at several locations in the three provinces and they also confessed to convening meetings to plan the fires" that occurred intermittently in September and October 2020, according to the justice ministry.
It said it documented 187 fires affecting 280 towns and villages last year.
They devastated 13,000 hectares of agricultural land and 11,000 hectares of forest land, while also damaging more than 370 homes, the justice ministry said.
At least three people were killed and dozens wounded, state media reported at the time.
Syrian law still provides for the death penalty for offences including terrorism, arson and army desertion, according to rights group Amnesty International.
In its latest death penalty report published this year, Amnesty International said it was able to corroborate information indicating that executions took place in Syria in 2020 but said it did not have sufficient information to give a reliable minimum figure.
The death penalty is usually carried out by hanging in Syria.