In this study, we aim to explore the conditions and constraints of implementing a lesson study-based professional development (LSPD) program for Japanese pre-service primary teachers. Based on the anthropological theory of the didactic--a well-established theoretical framework in mathematics education research--it offers three dimensions (institutional, educational, and personal) to frame and analyze the various conditions to implement the LSPD program and the constraints that impede them. We used a case study of an LSPD program for Japanese preservice primary teachers, which offered pre-service teachers an opportunity to engage in mathematics lesson planning and participate in a lesson study conference. The results illustrated the conditions of the institutional context in which the LSPD program appeared, and the constraints in the difficulty of making the lesson study and PD coexist. We also found that the personal constraints on pre-service teachers' lesson preparation work were affected by the conditions and constraints in other dimensions (institutional or educational). Thus, this study contributes to a deeper understanding of the constraints that may shape or hinder teachers' practice and knowledge in the LSPD program at diverse but interrelated levels.