The man was arrested after the “riot” at Westminster Hall, where the Queen is in state.
Met police officers detained the man around 10 p.m. on Friday after an incident that occurred when mourners entered the hall to pay tribute to the late monarch.
Mourners have been queuing for 13 hours or more to see the Queen before her funeral on Monday.
A woman standing in the hallway for the coffin alleged that her seven-year-old daughter had been pushed out of the way during the incident.
Tracey Holland’s mother said Sky News: “The police caught him within two seconds. We’re just trying to get her back.
“She got up from two in the morning and had been standing in line for 15 hours.”
It comes after a 19-year-old man allegedly exposed himself and stuffed himself into the mourners from behind as they waited in line at Victoria Tower Gardens on Wednesday.
It is said that Adio Adeshine traveled to the Thames in an attempt to avoid the police before he left and was arrested.
He was arrested on Friday after he appeared in the Westminster Magistrates’ Court on two counts of sexual assault and two violations of a sexual harm prevention order.
About the latest arrest, a Met police spokesman said: “At around 10pm on Friday 16 September, Met Parliamentary and Diplomatic Security Command officers detained a man in Westminster Hall in the aftermath of the riots.
“He was arrested for an offense under the Public Order Act and is currently in custody.”
Earlier in the evening, King Charles and his siblings took part in the vigil of the princes in the same room.
Along with Prince Edward, Prince Andrew and Princess Anne, the king stood silently by the coffin for 15 minutes, around 7:30 PM.
Public viewing of the coffin is scheduled to continue until 6:30 AM on Monday, the day of the Queen’s funeral at nearby Westminster Abbey.
As of 9:00 pm Friday night, the Department of Digitization, Culture, Media and Sports, lying in the state queue, said the lines were expected to run “at least 22 hours”, warning people “at night temperatures will be low.”