This study aims to run a circulation model of the collaborative process of reflection utilizing an
instructional expertise test as a measure for the improvement of teachers’ instructional expertise in the actual
classroom instruction and analyze the case. For this purpose, this study drew the concept of the instructional
maturation, explored the meaning and characteristics of instructional maturity, dividing it into five key scales
and presented a circulation model of the collaborative process of reflection drawing up it with four steps:
class formation, class reflection, classroom observation and instructional growth. Through the case of the
collaborative process of reflection applying this circulation model, this study examined whether the procedures
of the test-reflection-reexamination of instructional maturity were reflected meaningfully in the teachers’
instructional growth. In addition, this study analyzed whether the five key scales of instructional maturity (the
diversity, clarity, immersion, effectiveness and success rate of class) would be effectively applied to the
collaborative process of reflection. As a result of an execution of the circulation model of the collaborative
process of reflection with teachers who participated in a teacher learning community for one semester, it
greatly helps improve their collaborative instructional expertise. In particular, in the step of class formation,
teacher's routine class plan and execution led to the meaningful reflection and analysis of class through an
instructional maturity test; and in the step of class reflection, through the reflection of checkpoint by each
key scale of instructional maturity, fellow teachers’ instructional coaching and cooperation activity were
vitalized; and in the step of classroom observation, through reexamination of instructional maturity, class
reconstruction and reflection were achieved. In other words, according to the classroom situation, the steps of
class formation, class reflection and classroom observation are circulated and repeated, and ultimately, teachers
came to seek class growth. In addition, this study discussed measures for improvement to support the
collaborative process of reflection that lead the instructor’s reflection and the observer’s collaboration more
effectively based on the research results.