**Abstract**: Gravitational collapse is the one of the most important phenomena of gravity. About 20 years ago, Choptuik discovered a critical collapse in the massless scalar system. After this discovery, many author have shown that the critical behavior appears in the many systems, and it contains to the rich phenomena.

In particular, Okawa et al showed the massive scalar system, which has the typical length scale, has a non trivial phase diagram with respect to the critical collapse. In this study, we consider the spherically symmetric domain wall collapse. Because this system also has the typical length scale in the action, it is expected that this system also has the non trivial phase diagram. In order to analyze non-trivial phase diagram of this system, we study the gravitational collapse of this system around threshold of the BH formation. In this talk, as a first step of this study, I will show that the type II critical collapse appears in some parameter region in this system.

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This seminar is supported by Portuguese Funds through the CIDMA - Centre for Research and Development in Mathematics and Applications, and the Portuguese Foundation for Science and Technology ("FCT" - Fundação para a Ciência e a Tecnologia), within the project UID/MAT/04106/2013.