Carriedo, who has placed runner-up four times in the past two seasons, needed every bit of her four-stroke overnight lead to finish one clear of Sweden's Anna Berg and Germany's Elisabeth Esterl.
The 29-year-old from Zaragoza struggled to a three over par 75 in the final round for an aggregate five under par winning total, while Berg and Esterl posted 72 and 70 respectively.
Carriedo made life difficult for herself by bogeying the 16th but responded with a superb eight foot birdie on the 17th to draw back level with Berg at five under with just one left to play.
When Berg missed the green with her tee-shot at the 18th, the Spaniard was left with two putts for victory.
"Finally I've won, I was so nervous all day and fighting with myself," said an emotionally-drained Carriedo after collecting the £15,000 winner's cheque.
"I was swinging it too fast for most of the front nine, and leaving my ball too far away from the hole.
"So I just told myself to slow my swing down and things improved after that.
My putting wasn't very good today but I learned a very good lesson, that you don't have to play your best golf to win."
Taiwan's Yu Chen Huang led the local challenge and finished alone in fourth place on two under after firing a level par 72 in the final round.
England's Nicola Moult equalled the day's lowest score - a three under 69 - to take fifth spot at one under.