Third-seeded Bautista Agut saved five of the six break points he faced and converted three of his six chances to win in 1 hour, 42 minutes.
World No. 48 Rosol fired 13 aces to Bautista Agut's two, but the Czech was unable to prevent the 23rd-ranked Spaniard from claiming his second title in as many months.
Bautista Agut, who defeated defending champion and top-seeded Fabio Fognini on Saturday, claimed his maiden victory at `s-Hertogenbosch last month.
Rosol, who knocked out second-seeded Mikhail Youzhny of Russia in his semifinal, was also bidding for his second title after winning at Bucharest last year.