Semiconductor memory device and method of operating thesame

PURPOSE: A semiconductor memory device and an operating method thereof are provided to be able to reduce the time required for the read-out operation by performing the read-out operation to even memory cells or odd memory cells only in the read-out operation of data having the size of 1/2 page or less. CONSTITUTION: A page buffer group (150) comprises page buffers which are arranged to correspond to each bit line and classified to even page buffers and odd page buffers. A control circuit (120) controls the page buffer group so as to successively store data in odd memory cells through odd page buffers after successively storing data in even memory cells among memory cells through even page buffers. The control circuit controls the page buffer group so as to successively output read-out data from even memory cells in response to a half-page read command through even page buffers. [Reference numerals] (120) Control circuit; (130) Voltage generation circuit; (140) Low decoder; (160) Heat selection circuit; (170) Input output circuit; (180) Column address counter