Sea surface temperature (SST) data of one year from Advanced Microwave Scanning Radiometer for EOS (AMSR-E) are used to estimate statistically spatial and temporal scales of the global SST field. Using anomalies from the climatological annual SST variation, correlation coefficients in the horizontal space and time are calculated. Decorrelation scales, defined as an e-folding scale of SST anomalies, and signal-to-noise ratio are derived as functions of regional positions and calendar months. We assumed that the autocorrelation function of SST anomaly has anisotropic Gaussian characteristics in space-time domain. We evaluated the space-time scales and statistical errors in the SST data by fitting Gaussian function to the correlation coefficients using a least square method. Resultant zonal, meridional and temporal decorrelation scales range 1.5--3.0 degree, 1.2--2.0 degree and 1.5--3 day, respectively. The scales show geographical and seasonal differences, which means that dominant SST variability in the global oceans depends on regions and seasons.