Using the ecopsychological approach for mental development, the authors study the problem of cadets' creative imagination in the structure of their agency not by itself but in the holistic unity within the educational environment. In doing so, cadets' creative imagination is considered as the highest level of agency development. The type and direction of military higher school educational environment have been found by experimental means. The article demonstrates the resources of military higher school educational environment for cadets' creative potential development. The paper presents the experimental research results of dependence of creative abilities development level on cadets and instructors' interaction type.