"The operation, which we have prepared for some time with the United States, was carried out in virtually every region of the country, and the arrested men stem from every social category," police spokesman Soeren Kragh Pedersen told AFP.
"The offenders are liable for fines or up to one year in prison, according to the law, which bans any purchase or possession of pornographic material featuring children," he added.
Police arrested the suspects at 6:00 am (04:00 GMT) in their homes, where they confiscated computers and computer equipment.
The suspects "are for the most part men, of all ages and all social categories, who bought pornographic material with their credit cards. And what is most concerning is that there are teachers among them," criminal police chief Frank Jensen said.
The dawn raid came on the heels of an investigation in the United States where "the Americans noticed that Danish credit cards had been used to buy pornographic pictures and films featuring children, which allowed us to pick up the trail," Kragh Pedersen said.
He said another 18 people were supposed to have been arrested but "we did not find them at their addresses".
He did not rule out the possibility of other arrests after the 101 suspects arrested Tuesday were questioned.
National police chief Torsten Hesselbjerg said in a statement that the operation would "also have, we hope, a preventive effect, so that the demand for child pornography is reduced as much as possible."