This research aimed to find out the difficulties of students and the causing factors in solving mathematics questions viewed from the consept understanding on the fifth grade of SD Negeri Ciberem. This was a descriptive qualitative research. The data were collected using test, interview, and observation. The results showed that on the subject of upper concept understanding skill, students had difficulties in defining the concept and solving story questions. On the level of concept understanding skill, students had difficulties in defining the concept, solving questions, and calculating operation. On the level of lower concept understanding skill, students had difficulties in defining the concept, classifying object, presenting the concept in many kinds of representation, making examples and non-examples of denial, applying the concept or algorithm of problem solving, and calculating operation. Meanwhile, the causing factors were the factors of interest, motivation, intellegence, parents, and teacher.