We have cultured mesenchymal cells (MSC) on various types of ceramic disks and used these tissue-engineered ceramics for hard tissue regeneration. In this approach, observation of cultured cell morphology is important even if culture substrata are calcium phosphate ceramics, which usually show bioactive nature. However, due to the opaque nature of the ceramics, cells observation is very difficult. Here, we demonstrate light microscopic observation of rat MSC cultured on transparent β-tricalcium phosphate ceramics (β-TCP). The culture was performed in osteogenic medium. Thus, the cell differentiated into bone-forming osteoblasts, which fabricated a mineralized matrix on the ceramic disks. Microscopic observation revealed that the cascade of osteogenic differentiation after attachment/proliferation of MSC on the ceramic disks was similar to that on a culture grade polystyrene dish. These results confirmed the excellent property of β-TCP for MSC culture leading to hard tissue regeneration.