All 13 victims are from Vientiane.
Sojirat Kuyukham, 38, who owns and manages the business, was arrested.
Acting on a tip-off, an official disguised as a customer paid Sojirat Bt1200 for sex at the business. The official went into a room with a girl and phoned the joint team.
They invoked the martial law, which has been effective since May 22, to search the shop without a warrant. The officials seized Bt39,000, condoms, a pistol and five bullets, six bank accounts, two Laotian passports and a mobile phone as evidence.
Sojirat was charged with trafficking underage girls (older than 15 but younger than 18) and the procurement of underage girls into prostitution. Police also searched a nearby house and found 15 bank accounts, six of which belonged to Sojirat, and nine other bank accounts that were in the names of well-known people in Chumphon.