Region-based memory management scheme has been proposed for the programming language ML. In this scheme, a compiler statically estimates the lifetime of each object by performing an extension of type inference (called region inference) and inserts code for memory allocation and deallocation. Advantages of this scheme are that memory objects can be deallocated safely (unlike with manual memory management using malloc/free) and often earlier than with run-time garbage collection. Since the region inference is an extension of the ML type inference, however, it was not clear whether the region-based memory management was applicable to dynamically-typed programming languages like Scheme. In this paper, we show that the region-based memory management can be applied to dynamically-typed languages by combining region inference and Cartwright et al.'s soft type system.