In this paper we discuss that the two different plasma regions exist inside the plasma sheet during the magnetic reconnection in the magnetotail. The inner plasma sheet consists of a weak magnetic field and an isotropic plasma, while the outer plasma sheet contains the intermediate magnetic field intensity between the lobe and the inner plasma sheet and an anisotropic plasma. The plasma temperature parallel to the magnetic field is larger than the perpendicular temperature in the outer plasma sheet. On the basis of Geotail data analysis, we find that two different discontinuities are formed in the magnetotail: One is the slow-mode shock, and the other is the contact discontinuity. The slow shock downstream contains a contact discontinuity which separates the slow shock heated plasmas from the isotropic plasmas in the plasma sheet. ¿ 2000 American Geophysical Union