Nonvolatile memory device and method for operating the same

A nonvolatile memory device includes a page region including a plurality of normal cells and a plurality of auxiliary cells, a detecting unit configured to output a pass signal when at least one cell is programmed with a voltage higher than a reference voltage among program target cells of the page region, a count storing unit configured to store a count in the plurality of auxiliary cells during a first program operation for the page region, wherein the count indicates a total number of program pulses applied to the at least one cell until the pass signal is outputted from the detecting unit, and a voltage setting unit configured to set a program start voltage for a second program operation of the page region based on the count stored in the plurality of auxiliary cells.