The home side thoroughly deserved the points, and the scoreline somewhat flattered the visitors.
Airdrie forced three corners early on without creating an opening before Derek Adams fired a long-range shot over the crossbar as County responded.
Ross County came close to an opener in the seventh minute when Michael Gardyne latched on to a throughball from Sean Higgins, but Airdrie keeper Stephen Robertson raced off his line to divert the ball from the striker's path.
Higgins set up another chance six minutes later when he sent Martin Scott free, but the former Livingston player saw his shot touched behind for a corner.
But County took the lead from Derek Adams' flag kick when Andy Dowie rose above the Airdrie defence to head high into the net.
The Diamonds threatened on 21 minutes when Graeme Holmes hooked the ball into the County goalmouth but Gary Irvine deflected the ball for a corner.
A fine move on 34 minutes led to another goal for the home side. Higgins was again the provider with a defence-splitting pass and Gardyne swept the ball into the corner of the net.
County broke after defending Airdrie's fifth corner of the game and, after another flowing move, an Irvine cross into the box was headed against the base of the post by Diamonds defender Stuart Taylor.
Airdrie made a positive start to the second half and a Xavier Barrau cross was met at the back post by Brian McPhee but his header flew wide of the far post.
McPhee had another chance on 50 minutes when County lost the ball in midfield and the Airdrie striker raced in on goal but fired straight at Craig Samson.
But the Diamonds pressure paid off eight minutes later when a Barrau free-kick was only partially cleared and Paul Lovering drilled the ball home from just inside the box.
County almost restored their two-goal lead on 71 minutes when an Adams' shot was touched onto the crossbar by Diamonds keeper Stephen Robertson.
County substitute Fergus Tiernan charged in on goal in the dying minutes but his shot was well wide of target.
Samson pulled off a wonder save from Taylor in the final minute, and the visitors ended the match with ten men after Barrau picked up a second booking in stoppage-time.