The sprinter driver died in a head-on collision on the B68 between Bersenbrück and Badbergen in the Osnabrück district.
According to the police, the man started overtaking on Thursday afternoon despite oncoming traffic.
A car could still evade, an oncoming truck no longer.
"The cause is very clear, there are witnesses and clear leads," said a police spokesman.
Osnabrück - The driver of the oncoming truck was slightly injured.
dpa