Ngo Sy Tai, also known as Hung Sy Truong, is wanted in Belgium over allegations he ran a so-called "safe house" for his fellow Vietnamese nationals in Anderlecht, Brussels.
Joel Smith, representing Ngo, appealed against extradition and cited a lack of detail in the charges against his client, meaning he was unable to sufficiently advise him.
But District Judge Mark Jabbitt, in his written ruling handed down at Westminster Magistrates' Court on Thursday, said Ngo should be extradited.
He faces up to 20 years in prison if he is convicted over the operation, an extradition hearing at the same court heard last month.
Ngo, who is said to be 18, fled to Berlin and then to Birmingham following the grim discovery of the 39 dead men, women and children in an airtight trailer the morning after it left the Belgian port of Zeebrugge, bound for Britain, on October 22, 2019.
The victims, 10 of whom are said to have passed through Ngo's four-storey terraced safe house on a quiet backstreet, had hoped for a better life in Britain when they agreed to pay up to 13,000 pounds (US$17,860 dollars) a head for a "VIP" smuggling service.
The court heard Ngo, who would therefore have been just 16 at the time of the deaths, is accused by Belgian authorities of being a member of a criminal organisation, being involved in human trafficking and using forged documents.
Outlining the case for the Belgian authorities, Daniel Sternberg said: "He (Ngo) is described as an organiser for the people-trafficking organization, arranging accommodation and transit for money.
"The vulnerable position of the people who paid money to be smuggled was abused and minors were also abused.
"A criminal attitude on the part of Ngo and others amounted to gaining money with total disregard to the physical and psychological impact on the victim."
Sternberg said the migrants kept at the safe house were "forbidden to leave, and were obliged to be silent during their stay."
He said Ngo also arranged for taxis to take the Vietnamese migrants to a location near the France-Belgium border before they were put on to the lorry bound for Britain.
Sternberg said there was "sufficient evidence" to bring a case against Ngo, potentially this summer.
The matter will now be sent to the Home Office for the Secretary of State to rubber-stamp extradition, pending any appeal by Ngo's legal team. - dpa