Japan opened the scoring after nine minutes through Takahiko Yamabori but Pakistan, who were edged out in a gripping semifinal by China two days ago, responded immediately with a penalty corner from Maqsood Adnan.
Pakistan went 2-1 ahead just before half time when Abbasi Shakeel scored from open play.
A brace of strikes just after the interval from Muhammad Waqas put the result beyond doubt before Yamabori netted his second of the game late on.
India rounded off a disappointing tournament on a high note with a convincing 4-0 win against Malaysia for fifth place. It is the first Asian Games that India's men have departed without a hockey medal but two penalty corner strikes from Ragunath Vokkaliga at least gave them a consolation success.
"We had to prove that we are a team that could play in the finals,"Â said Vokkaliga. "It was a good game for us. We had to prove that we could beat other teams.
Bangladesh defeated Chinese Taipei 5-1 to finish in seventh place.
15th Asian Games, Doha 2006