In this paper, I examine the traditional distinction among distributive predicates, mixed predi- cates, and collective predicates, focusing on mixed predicates and collective predicates. Under the traditional three-way distinction of predicates, a mixed predicate can be both a collective predicate and a distributive predicate because a plural noun in a mixed-predicate sentence is ambiguous be- tween a distributive reading and a collective reading. In this paper, adopting Winter’s (2002) analysis of set/atom predicates, I argue that mixed predicates are atomic predicates, whereas col- lective predicates are set predicates in Japanese. Support for my proposal comes from distributive and collective readings in the Japanese Floating Quantifier Construction (henceforth, JFQC). When a verb composes with a classifier to denote a set of sets in the JFQC, there is a sharp contrast between the mixed-predicate JFQC and the collective-predicate JFQC, which is problem- atic for Link 1983 and Landman 1989. When a verb composes with a classifier to denote a set of sets in the JFQC, a mixed predicate, which is an atom predicate, can have only a distributive read- ing, whereas a collective predicate, which is a set predicate, can have both a distributive reading and a collective reading. In my analysis, this difference can be reduced to the properties of an atom predicate and a set predicate, as proposed by Winter (2002).