A process for producing a high purity trialkanolamine excelling in hue and having an APHA of not more than 40, characterizing by including producing a mixed alkanolamine by the reaction of an alkylene oxide with ammonia; removing low-boiling substances from the mixed alkanolamine; removing high-boiling substances by subjecting the product deprived of the low-boiling substance to vacuum distillation, and redistilling the distillate obtained by the vacuum distillation.