The van lost control and flipped onto its side early that morning inside the Michinoku Tunnel on the route between Aomori City and the town of Shichinohe, Asahi Broadcasting Aomori reported. Six Vietnamese nationals aged in their 20s to 30s were on board.
Four passengers escaped after the vehicle overturned, but two remained trapped when a large truck collided with the van a few minutes later. The impact crushed the van and scattered debris, cargo and personal belongings across the road.
All six occupants were taken to hospitals; one male passenger was later pronounced dead, police told Nippon Television Network. The toll road was closed for about four and a half hours before traffic resumed.
Police said road surfaces were slippery at the time. The van was fitted with regular tires while the truck had winter tires. Investigators are examining the circumstances of the accident, including whether road conditions contributed.