Location of defects in solid can be presumed in terms of arrival time differences of AE-waves to each sensor. A small amount of the arrival time error, however, might influence on the AE source location. Present paper investigates the influence of errors including both the arrival time and sensor location on the AE source. Superiority of the neural network technique over the least square method was discussed on accuracy of location obtained by the arrival time differences. Applicability of source location using simulated AE source to real structure of pipe was also discussed. It was concluded that the neural network technique should provide available means to the AE source location because of less influence characteristics from the noise.