It happened around 3 p.m. at the north security checkpoint, lane three.
Officers spotted the Sig Sauer Model P229 .40 Cal handgun just as the man was passing through the X-ray machine at the airport checkpoint.
The gun was inside the passenger's carry-on bag.
To date, TSA officers have detected five firearms at CLE checkpoints this year. TSA found 19 firearms at CLE last year.
According to TSA, there is a right way to travel with a firearm and a wrong way. The wrong way is to bring it to a checkpoint. Passengers are permitted to travel with firearms in checked baggage if they are unloaded, packed in a hard-side case, locked, and packed separately from ammunition. Then the firearm must be taken to the airline check-in counter.