Can the Nambu-Goldstone Boson Live on the Light-Front?

We show that the Nambu-Goldstone(NG) boson restricted on the light-front(LF) can only exist if we regularize the theory by introducing the explicit breaking NG-boson mass \(m_{\pi}\). The NG-boson zero mode, when integrated over the LF, must have a singular behavior \(\sim 1/m^2_{\pi}\) in the symmetric limit of \(m^2_{\pi}\rightarrow 0\). In the discretized LF quantization this peculiarity is clarified in terms of the zero-mode constraints in the linear \(\sigma\) model. The LF charge annihilates the vacuum, while it is not conserved in the symmetric limit in the NG phase.