The man, aged 24, was accused of raping more than 10 elderly people whom he took care of in an elderly care institution during 2013 to 2014, Xinhua quoted Finnish daily Turun Sanomat as saying on Wednesday.
The victims, who were 74 to 100-years-old, suffered from memory disorders and part of them had difficulties in walking.
According to the court, the man should have been sentenced to 12 years in prison, but just 9 years of unconditional imprisonment was imposed on the suspect, because he had provided assistance in investigating the case, where no witnesses or victims could tell anything.
In addition to the imprisonment, the court also ordered the male nurse to pay a total of 18,000 euros ($20,110) to the victims for compensation.
Helena Monttinen, unit director from Finnish National Supervisory Authority of Welfare and Health Valvira, told the daily that at the moment it is difficult to say whether the supervision over the elderly care should be tightened or changed.