The purpose of this study was to examine the relationship between obsessive-compulsive tendency (hereafter referred to as “OCT”), perfectionism cognition and mental health among university students. The participants included 125 female and 27 male university students. We constructed a model including these three variables. A path analysis revealed that personal standards of perfectionism cognition had a negative influence on the checking and indecisiveness of OCT. Further it revealed that the pursuit of perfection of perfectionism cognition had a positive influence on checking and washing of OCT. The results suggest the following two important points: First, checking and indecisiveness with high OCT people may be suppressed effectively by focusing on not adaptive cognition (e.g. personal standards) but maladaptive cognition (e.g. concern over mistakes) by intervention for cognition (e.g. cognitive therapy). Second, it may be necessary for people who have checking or washing tendencies to approach not only their anxiety but also “incompleteness”.