The know-how of critical thinking is tacit and latent, and the importance of training critical thinking skills is widely recognized. For those reasons, it is difficult (i) for learners to develop meta-cognitive skills, (ii) for teachers to externalize their tacit know-how of critical thinking, and (iii) for system developers to embed active learning support functions into the system that follow a learner’s thinking processes. To support meta-cognitive learning, CSCL is a promising approach, although we must design functions well to facilitate learner and teacher behaviors (communications). In this paper, we propose a learning-phase model that specifies learning goals and scaffolds for respective learning phases. Furthermore, we illustrate a development system for a nursing domain according to the model. We expect that the model-based system will contribute to encouraging meaningful learning behaviors.