The purpose of this investigation was to examine the effects of children's ages and their age differences on ‘the objections’ between young children in a nursery school. Subjects were 14 children in a same two-year- old class. They were divided into three groups in terms of their ages: H group (four children: mean age 33.0 months); M group (six children: mean age 29.3 months) ; L group (four children: mean age 27.5 months) in May 1993. The data were obtained from the observations of free play from May 1993 to March 1994. The main results were as follows: (a) the frequency of objections did not change through a year ; (b) L group children tended not to object to H group children at first ; (c) but the peer relationships were gradually changing for the equality ; (d) ‘the situation of objection’ and ‘the content of objection’ depended on children's ages.