The man was detained on Monday in the northwestern city of Ponferrada in the province of Leon, and police are looking for a second suspect, a spokesman for the provincial government said.
Police launched their investigation after a group of over 100 people, purporting to celebrate a baptism, enjoyed a 2,000-euro ($2,100) banquet on February 27 at the Hotel Carmen restaurant in Bembibre, northern Spain, before promptly doing a runner.
"They were dancing, then suddenly they had disappeared. In one minute, a hundred people had left," restaurant boss Antonio Rodriguez told Cadena Ser radio.
"They didn't leave in little groups -- no, they went all at once."
It later emerged that another restaurant about 10 kilometres (six miles) away in Ponferrada was also the scene of a similar heist in mid-February -- that time by a group of around 200 people.
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They were allegedly celebrating a wedding, when they also fled without paying a bill of some 10,000-12,000 euros.
The authorities believe the two cases are linked.
The arrested man posed as the godfather of the baptised child and the father of the groom when he made the bookings, local newspaper Diario de Leon reported.
The spokesman for the Leon provincial government did not confirm media reports that the suspect was a national of an eastern European country.
