If you mean, do you have to pay to enter, then yes. It costs money to enter, and it costs extra to get that bracelet that lets you go on every ride. Although, in the park you can buy tickets for just one or two rides if you wish.
On Zealand (Sjælland) there is one free amusement park that I know of. It’s called ‘Dyrehavsbakken’ or just ‘Bakken’. Entering is free, but going on rides costs money.