Provided is a storage device that performs a read operation by using a time interleaved sampling page buffer. The storage device controls a sensing point in time, when bit lines of even page buffer circuits are sensed, and a sensing point in time, when bit lines of odd page buffer circuits are sensed, with a certain time difference, and performs an Even Odd Sensing (EOS) operation in a stated order of even sensing and odd sensing. The storage device performs a two-step EOS operation and performs a main sensing operation on a selected memory cell according to a result of the two-step EOS operation.