Temporal sea surface elevation data picking up giant freak waves with wave heights exceeding 2H(1/3) and 10m are analyzed to investigate their statistical characteristics. The freak waves occur in sufficiently developed a seasonal wind wave field with and unidirectional spectra having steep single peak and obeying the wind wave low of f(-4). The crest and trough amplitude distributions of the observed sea waves including the freak waves are different from the Rayleigh distribution, although the wave height distribution fairly agree with the Rayleigh distribution. The run length distribution of the observed observed waves are also examined and found to be well predicted by the Kimura theory.