This study proposes an algorithm for the passage of a mobile robot group through a narrow space. We deal with a robot group composed of one leader and multiple unlabeled followers. A steady formation is realized by generating a Delaunay diagram using the profiles of surrounding robots. Further, we resolved a deadlock situation by using the phase gap of nonlinear oscillators to which the profiles of the surrounding obstacles are provided as inputs.We implement the proposed system in a real multi-robot system in order to demonstrate its effectiveness.