The purpose of this study is to investigate both the characteristics of private speech, type of play, and peer involvement in the sociodramatic play and the correlation of private speech, the play type and the peer involvement. For this study, 15 children at 3 and 5 years old were observed, and observation scenes were transcribed and analyzed. The results of this study as follows; First, there was no difference in the amount of private speech between 3 and 5 years. And in all ages, \'fantastic play and sound effects\' was observed most frequently in the private speech of sociodramatic play. Second, there were some differences by ages in the play type and peer involvement. Third, there were the most positive correlations between categories of private speech and fantastic play in play type as well as between categories of private speech and solitary play in peer involvement.