The arrest was the first known case of anyone being detained for reading as a form of protest since the military seized power last month.
Handfuls of anti-coup protesters have staged several silent readings of the classic book elsewhere in the capital in recent weeks because they say its indictment of totalitarianism has become relevant after the army deposed the country's elected government in a May 22 coup.
A police officer said all the arrests took place in and around Siam Paragon, a crowded, upscale mall in downtown Bangkok that is one of Southeast Asia's largest. It was the world's most photographed location on Instagram last year.
The officer spoke on condition of anonymity because he is not authorised to give information to the media.
A reporter who witnessed the lone man reading Orwell's book said he was taken away by half a dozen plainclothes police. The reporter, who asked not to be identified because of the sensitivity of the situation, said the man first read the book quietly, then held it up as officers approached and journalists took photos.
When questioned, the man said he was reading the book for "liberty, equality and fraternity" — the slogan of the French Revolution. The man was also playing the French national anthem on his smartphone, the reporter said.
Several other people were also detained in the shopping mall's food court for preparing to hand out sandwiches, mimicking another recent protest in which a small group of student activists from Bangkok's Thammasat University gave out what they said were "sandwiches for democracy".
The eighth arrest Sunday was of a woman wearing a T-shirt with the words "Respect My Vote" on it. The phrase became popular among pro-democracy groups trying to counter anti-government protesters who obstructed elections on Feb 2 that were later annulled in a controversial court ruling.
The protesters had accused the then government of corruption and abuse of power, and had repeatedly called for it to be overthrown and urged the army to intervene. The government, meanwhile, had argued that the nation's fragile democracy was under attack by protesters, the courts, and finally the military which staged the coup.
The junta that took power last month has proven to be one of the most repressive regimes in Thailand in more than four decades. Military authorities have made clear they will tolerate no dissent. They have summoned hundreds of people perceived as threats to public order - mostly members of the ousted civilian government, activists and intellectuals; most of those released have had to sign pledges saying they will not instigate unrest.