Police arrested a 31-year-old man for allegedly taking upskirt photos of women, including 39 actresses, and selling their photos and videos online.
Worasak Sriworawibul was arrested at his home in Chon Buri.
Police seized two computers, four mobile phones and a small camera at the suspect's home.
The man uploaded 259 upskirt videos of women, including students, to a Russian online service, for members who paid subscription fees, police said.
Police advised women who wear short skirts to beware of anyone approaching them from behind and acting suspiciously.
Police said Mr Worasak confessed that he approached the victims from behind, lowered himself and pretended to tie his shoelaces while using his phone for taking upskirt photos and videos.
The suspect admitted to committing the crime for about four years.
Police said the man also took upskirt photos of 39 actresses who attended events, but the suspect denied he had shot the pictures, saying he received them after exchanging clips with group members.
