Police reportedly got the man to return the speaker to its owner, a teenage boy who was travelling to Madrid with his mum.
His mum told Diario de Ibiza: "The police told me it was the third day the man had been working at the airport and returned the speaker to me immediately.
"I was very grateful because I had bought it for my son's birthday."
It is understood the man, who police say confessed to taking the speaker, will face court over the alleged theft.
This is far from the first time airport staff have been caught mistreating passengers' luggage.
In May, Courier-Mail reporter Vanessa Marsh captured a ground crew member throwing luggage carelessly at Honolulu airport while loading up a flight to Phoenix.