Non volatile memory device and method of operating the same

PURPOSE: A non-volatile memory device and an operation method thereof are provided to reduce a program operation time by efficiently reducing a verification time by controlling a frequency of verification voltage level change of fast verification. CONSTITUTION: A memory cell array(310) comprises memory cells for data storage. The memory cells are connected to a word line and a bit line. A page buffer part(320) is connected to the bit line. The page buffer part latches data stored in a selected memory cell. An Y decoder(330) offers a route for data input/output of page buffer circuits of the page buffer part. An X decoder(340) selectively connects the word line of the memory cell array. A temperature sensor(360) outputs a temperature sensing signal by using reference voltage differently inputted according to ambient temperature. A controller(350) controls a verification frequency according to the temperature sensing signal.