The street is popular with tourists for its outdoor market and snack stalls.
The people injured in the attack included nine tourists and a seven-year-old child.
Police were initially reported to have arrested the alleged culprit in that attack, a Chinese man in his 30s, after they found him on the roof of a nearby building.
But officials later clarified that the man was actually arrested for skipping a court date in an unrelated white-collar crime case.
Since late 2008, there have been at least six acid attacks in several shopping districts across Hong Kong, leaving more than 100 people injured.