Understanding the factors that determine whether consumers choose options or not is critical for developing marketing strategy. When consumer preferences are constructed in the process of making a choice, different contexts and tasks lead to different aspects of the option. The preference construction are sensitive to the ease or difficulty with which the informations are processed. The author examines how the preference fluency that is defined as the subjective feeling of ease or difficulty experienced while making a decision affects the consumers' positively behaving intents such as purchasing intention and positive words of mouth, and focuses on metacognitive experiences that occur at the process of constructing preferences. Responses to new informations may depend on metacognitive feeling of the ease or difficulty with which consumers perceive or understand the informations. Sources of fluency experiences arise from the ease with which externally presented stimuli are processed. The processing fluency may be conceptual or perceptual in nature. The ease with which consumers can identify a target stimulus on subsequent encounters and involves the processing of physical features,such as modality and shape(Jacoby and Dallas 1981). Conceptual fluency reflects the ease with which the target comes to minds and pertains to the processing of meanings(Lee and Labroo 2004). The two types of processing fluency are distinctive. The few studies that examine the effects of conceptual and perceptual fluency focus more on how they affect the perference fluency than on how they do evaluation. The objectives of this research are to explore the mediating roles of preference fluency between the processing fluency and positively behaving intents. Perceptual fluency and conceptual fluency are distinctive constructs that have unique components different from each other. But their roles in fluency-based preference construction are less clear. By reviewing the theoretical background of processing fluency the components of each fluency have been explored to develop the questionnaire to test the relationship between conceptual fluency and preference fluency, and between perceptual fluency and preference fluency. And to explore the relationship between preference fluency and positively behaving intents,this article extends roles of processing fluency to the functions toward the preference fluency to verify the roles mediating between processing fluency and positively behaving intents. Taken together, the hypotheses that indicate preference fluency are mediator between processing fluency and positively behaving intents are developed. Four types of scenarios and advertisements are concerned with two high and low processing fluencies. The hypotheses are tested by using Amos18. The results of testing hypotheses show the mediating roles of preference fluency on the effects of perceptual fluency and conceptual fluency on positively behaving intents such as purchasing intents and positive words of mouth. And there are no direct effects of each processing fluency on the intents. A key finding from preceding studies on preference construction is that preferences vary across situations and time, option-framing, choice contexts. To the extent that positively behaving intents vary in the mode of presentation and consumers vary across contexts and time in their ability to construct preference about a particular brand, preference fluency are the major factor that marketer must give attention on. To improve preference fluency many variables present in consumer environment, such as cognitive load, concreteness of presentations, exposure frequency, meaning of consuming brand, relationship between the meaning and consumption goal, etc. should be considered and rearranged.