The accident occurred at 2 o’clock on Saturday afternoon in the village of Skee, 5 kilometres outside Strömstad.
“It happened when he was cutting the grass on a slope. The lawn mower overturned and the man died when it landed on top of him,” police spokeswoman Pia Goksöyr told news agency TT.
Ambulance staff pronounced the man dead when they arrived at the scene of the accident.
“A post mortem examination will be carried out to establish the cause of death,” said Goksöyr.