A man and a woman in their 60s were found dead in a house in Suberg last Wednesday.
The suspect was arrested the following day.
During the course of questioning he admitted killing the married couple, Bern police said in a statement on Monday.
Investigations show that the couple died from the effects of blunt trauma.
Police believe it was a family drama, though due to the ongoing investigation they have not said how the suspect is related to the deceased couple.
The exact circumstances for the crime and the suspect's motives are yet to be established.