The ministry said that the raids, which took place in seven federal states, targeted sites linked to the "Kingdom of Germany" group and the homes of its prominent members on Tuesday.
German Interior Minister Alexander Dobrindt said the group's 6,000 members had established a "counter-state" in Germany and were undermining the rule of law and the state's monopoly on the use of force.
He added that they "support their supposed claim to power with anti-Semitic conspiracy narratives."
The ministry explained that the order to ban the group was issued prior to the raids.
Germany's domestic intelligence agency placed the Reichsbürger movement under surveillance in 2016, shortly after one of its members shot a police officer during a raid on his home.
Supporters of the movement believe that current German democracy is merely an illegitimate facade, and that they are citizens of a monarchy that, they say, has continued after Germany's defeat in World War I, even though it has been officially abolished.
