Police are investigating a young child's hands becoming trapped under the heavy door of an electrical cabinet at Linnanmäki amusement park on Friday evening.
The child was taken to hospital for further treatment.
No individual is currently suspected of a crime. Police are initially investigating the incident as a suspected case of negligence resulting in injury.
"I cannot comment on the circumstances of an individual customer's case at this stage. We are working with the authorities to establish what happened," Linnanmäki spokesperson Niina Häkkinen told Yle.
The incident follows another mishap at the amusement park in June, when four people were rescued from the Salama ride after it stalled.
Rescue services said the passengers spent around half an hour in the carriage before being safely brought down by ladders, with ropes used to secure them during the operation. No one was injured.