The main purpose of the present study was to examine what kind of criticalthinking attitude university students have in reading non-academic materials. After having the class of actual proof procedure in psychology, 252 university students read a material containing fallacious before-and-after arguments. They were asked to provide their opinions, the reasons why they think so, and how to proof their opinion. The results showed （1） the students have agreed with the argument （the argument which seemed to reflect non-critical thinking attitude）and the students having disagreed with the argument （the argument which seemed to reflect critical thinking attitude） were half-and-half ;（ 2） their reasons were quite different between agreeing students and non-agreeing students and（3） only 68 of 252 students （27％） displayed critical thinking abilities.Furthermore, ten percent or less showed which is considered as the logicalthinking in verification. These results suggest that the majority of the studentsdid not read these non-academic materials from a logical point view, although students were given prior information on validation methodology. It is required to examine how naive theory affect ctitical thinking.