In the present talk, we will show how the axial-vector meson emerges as a quasi-bound state consisting of the kaon and anti vector kaon or a hadronic molecular state. We first construct a dynamical model for scattering based on the fully off-mass-shell coupled-channel formalism. The model includes both the and channel. The axial-vector meson resonance is generated dynamically below the threshold without any explicit resonance included. It reveals a certain similarity to the case of scalar meson (980), which is well known as the molecular state of the . This implies that the resonance can be theoretically interpreted as molecular state or quasi-bound state. We compare the present result to the experimental data on the charge-exchange reaction and finds that it is in good agreement with the mass spectrum corresponding to .