"If a man forces a woman to tolerate him putting his fingers in her genitals, then the incident has a tangible sexual character that is capable of violating her sexual integrity. It is therefore a question of a punishable sexual act," the Supreme Court wrote in a statement on Thursday.
"The circumstances in this case are such that the act shall be deemed as rape, no less aggravated rape."
The man had previously been convicted of rape by a lower court after he tore off his girlfriend's clothes and forced his fingers into her genitals on suspicion that she had been unfaithful, legal trade publication Dagens Juridik reported in Februrary.
The lower court had also convicted the man of several other charges related to repeated assaults and threats directed against girlfriend in a relationship that had been marked by jealousy and suspicion.
In reviewing the case, the Svea Court of Appeal threw out the rape conviction, arguing that the man's actions weren't sexual in nature. Both the man and his girlfriend testified that the act was an attempt to ascertain whether or not the woman had engaged in sexual activity with another man.
"His action can therefore not be seen as having a sexual character such that it can be regarded as a sexual act according to the criminal code," the lower court wrote in its ruling at the time.
The Supreme Court rejected these claims, however, arguing that it is a sexual act to force "fingers or objects in a woman's genitals. The purpose of the incident is irrelevant," it claimed.
The fact that the incident is deemed as rape is due to the fact that the man used violence and threats when he "dug around" in the woman's genitals, the court said.
The Supreme Court has also requested that the Svea Court of Appeal address questions about penalties and damages.