Swedish counter-terrorism police found four mobile phones and two computers in a raid on Wednesday on an apartment in Malmo, Sweden's third largest city, where one of the Brussels attacks suspects grew up.
The court ordered the six items sent to Belgian investigators, the prosecutor in charge of the case, Hans Ihrman, told AFP.
"They are important for the investigation," he said, without specifying how the possessions were connected to the 28-year-old suspect, Osama Krayem.
A surveillance video showed him accompanying Khalid El Bakraoui, the Brussels metro suicide bomber, minutes before the attack.
Held in Belgium since his arrest, Krayem is believed to be a link between the cells that attacked Paris in 2015 and Brussels. He has been charged in both investigations.