&nbsp;Self-Renovation(SR), which can be defined as customizing house done by tenants themselves, or some construction company with tenant&rsquo;s planning, is focused in this report.<br>&nbsp;The purpose of this report is to clarify the relationship between rental systems of contract, management and space of dwelling units and self-renovation by tenants in rental apartment houses. We interviewed 23 lenders, such as real estate agency, building owners, property management company and designers of house renovation, about a lease contract and condition of dwelling units. Additionally, we visited 40 houses and interviewed residents the process of SR, satisfaction and feeling of attachment to their house, and surveyed SR by recording part and taking the photograph.<br><br>&nbsp;What we can conclude from this report is the following.<br>&nbsp;&middot; The Rental system that allow tenants to renovate their house by themselves realize the modernization and personalization of dwelling unit and increase tenants satisfaction and feeling of attachment to a dwelling unit.<br>&nbsp;&middot; We showed that rental systems have two tendencies. The first one has soft mechanism that encourages tenants to do SR aggressively and hard condition that has a lot of room for SR. This collaborative rental system could realize personalized modernization of dwelling units by large scale SR. The second one has soft mechanism that weakens motivation to do SR and hard condition that has a little room for SR because lenders renovated dwelling units in advance. This simple and easy rental system could encourage tenants to personalize dwelling units by small scale SR.<br>&nbsp;&middot; It is assumed that regeneration of old and decrepit dwelling units should be done in collaboration with lenders and tenants. Owing to this, we indicated that it is important to coop with various tenants flexibly and to prepare mechanism to reduce the burden of SR.