This paper presents a study on developing of a new exoskeleton for ankle joint rehabilitation with three degrees of freedom (3 DOFs). The primary attention is paid to the process of designing and modelling the device aimed at restoring the lost functions of joint mobility. The authors carried out a complex analysis of the functional requirements of the exoskeleton based on the research of potential user’s needs, which allowed them to develop a conceptual model of the proposed de-vice. In this study, a prototype of the exoskeleton is designed using modern additive technolo-gies. A prototype of the proposed device underwent virtual testing in conditions maximally close to the real one, which confirmed its effectiveness and comfort of use. The main results of the work indicate the promising potential of the proposed solution for application in rehabilitation practice, especially for patients with ankle joint injuries and diseases.