The soldiers, two sergeants from the national guard, were stabbed to death near a bar in the capital, Caracas, last weekend.
The crime has shocked the country, as the ages of the children now in custody range from six to 15 years.
They are said to belong to a gang called Los Cachorros (The Puppies).
The sergeants, Yohan Borrero and Andres Ortiz, were wearing civilian clothes at the time of the attack.
They were smoking cigarettes outside the bar in the early hours of Sunday when two children approached them and stole one of their bags.