Recently in a neutrino reaction experiment large cross sections due to the neutral current were observed. In order to incorporate tho neutral current into weak-interaction theory, the quantities on the neutral current were calculated using the quark (spin-1/2)parton model and making the additional assumptions that the neutral-current intemction is described by the current- current type, the current is of V--A type, and the contributions from the neutral partons can be neglected. Cross sections for neutrino and antineutrino interactions with protons and neutrons are calculated. (JFP)