The shooter attempted to kill himself but survived with injuries, YLE radio said, citing police.
Tapio Varmola, the principal of the Kauhajoki School of Hospitality, was quoted by the radio station as saying the attacker opened fire on a group of students that were taking a test in class around 11 a.m. local time (08:00 GMT). Some 150 students were on the school premises at the time of the shooting.
Several videos have been discovered on YouTube in which a young man who says he lives in Kauhajoki and is 22 years old is shown shooting pistols at a firing range. The videos were posted on the site five days ago, but have now been removed, YLE said.
The incident resembles a school shooting last November, in which an 18-year-old student shot dead six fellow students, a nurse and the principal before killing himself in the town of Jokela in southern Finland.
