Image pickup device and method of extending dynamic range thereof

A photographing device and a dynamic range extending method thereof are provided to increase power of an output signal by using current frame data and previous frame data, thereby suppressing increase of noise as extending the dynamic range of a low gradation image signal. A luminance and chrominance signal generating unit(160) generates a luminance signal and a chrominance signal. A dynamic range extending unit(170) extends a dynamic range of the luminance signal and chrominance signal, generated by the luminance and chrominance signal generating unit, based on current frame data and previous frame data. The dynamic range extending unit comprises a motion detecting unit, a data merging unit and a gain determining unit.