A problem is to provide, in the field of polyhydroxy polyurethane resins the development of applications of which has not moved ahead by conventional technologies, a self-crosslinking polyhydroxy polyurethane resin, which enables to provide products, such as imitation leathers, excellent in abrasion resistance, chemical resistance, heat resistance and the like, and moreover, which is useful from the viewpoint of a reduction in greenhouse gas, contains carbon dioxide incorporated and fixed therein, and is responsive to environmental conservation. Provided are a self-crosslinking, polysiloxane-modified, polyhydroxy polyurethane resin having masked isocyanate groups in a structure of a polysiloxane-modified, polyhydroxy polyurethane resin derived from a reaction of a 5-membered cyclic carbonate compound and an amine-modified polysiloxane compound and having polysiloxane segments therein; a production process of the self-crosslinking resin; a resin material containing the self-crosslinking resin; and an imitation leather composed of a base fabric and a resin composition composed of the self-crosslinking resin as its principal component and impregnated in or laminated on the base fabric.