At a press conference Tuesday with his German counterpart Frank-Walter Steinmeier, the Nigerian minister did not mention a specific date for the girls' release, but said he was hopeful it would be soon.
Steinmeier said he shared his colleague's confidence after the Nigerian Army and Boko Haram reached a ceasefire deal last week.
Germany's top diplomat is set to visit Nigeria next week along with his French counterpart, Laurent Fabius.
The US administration confirmed Monday that a ceasefire agreement had been reached between the Nigerian Army and Boko Haram, but it said that negotiations on the girls' release were still going on.
The girls, who were abducted by the Nigerian jihadis April in a raid on their school in the town of Chibok, might be freed this week in Chad, which hosted the negotiations with the terrorist group, Nigerian officials told EFE.
Boko Haram has threatened to sell the kidnapped girls if the Nigerian authorities do not free its jailed militants.
Since it emerged in 2009, Boko Haram has killed over 5,000 people in its campaign to impose Islamic sharia law in the poverty-stricken Muslim-majority north of the country and reject Western values.