This study is a case report of the cognitive counseling for a child who has difficulty with solving ratio-word-problems. The child in this study was a first-year junior-high-school female student. It was difficult for her to explain her idea in words. It seemed that the student has poor verbal working memory. To support her learning of ratio word problems, we used diagrams as an external resource for her thinking about meaning of the problems. In addition, we helped her use metacognition with cards that showed points to be paid attention to in the process of solving the problems. Our supports improved her performances of ratio word problems, and she came to draw diagrams spontaneously. In addition to that, she became able to control and monitor the process of calculation by herself.