The equation of state in the lower density region up to the nuclear saturation density is becoming to be determined, but still there exist uncertainties. Especially, it is difficult to experimentally determine the parameters corresponding to the incompressibility of nuclear matter and the density derivative of symmetry energy. On the other hand, the neutron stars produced after the supernovae realize the ultra-high density inside the star. Thus, the neutron stars might be a suitable “laboratory” to see the properties of high density region. In practice, via the observations of the stellar oscillations and/or the gravitational waves emitted from such compact objects, one could make a constraint on the equation of state. In this talk, using the asteroseismology in neutron stars, we discuss the possibility to constrain the equation of state of nuclear matter.