Geometric shapes around us are the initial conceptions for the mathematical thinking. Geometric thought develops throughout the interval from a concrete level of geometric understanding to an abstract level of geometric perception. Many studies have described students' geometric understanding using the van Hiele levels of geometric thinking, which help the teacher to understand his/her students' development of geometric concepts. The purpose of this case study was to explore a sixth grade student's geometric thinking based upon the van Hiele levels of geometric thought, in relation to his attitudes toward mathematics and to discuss whether or not it is a constructivist approach to use the phases of instruction of van Hiele levels of geometric thinking.