The purpose of this thesis is to search the situation of an outbreak of the fallacy and methods of its treatment. We regard intuition as origins of genuine knowledge, but it sometimes raises the fallacy by intrinsic characters of itself. It makes an examination of the fallacy of the sense of sight like an optical illusion to instance that of sense. The sense of sight is an important factor in an intuitive cognition. However, its activity without thinking raises the fallacy of intuition in the process to observe and judge the things. I point out the fallacy of intuition which originates from terms and concepts in mathematical problems. The concept of mean velocity is representative. In this case, students make a mistake which means velocity can be solved by dividing the sum of v$_1$ and v$_2$ into two. The methods which overcome the fallacy of intuition are balance of intuition and logic, overcome of functional fixedness, the development of intuitive models and the development of metacognitive ability.