Politeness is the phenomenon of Pragmatics. Leech proposed six maxims and approbation is the most important maxim. (a) Minimize dispraise of other; (b) Maximize praise of other. Based on the approbation, the paper conducts a research on the Japanese daily language. We can learn that the everyday acts of courtesy and a variety of social etiquette in fact can be attributed to the Leech's politeness principle. The most important approbation governs the polite words and deeds in daily life. Therefore, we should use the language which benefit others, so that the personal relationship can be coordinated developed.