Metal-supported solid oxide fuel cell (MS-SOFC) requires not only high electrochemical performance and durability but also high volumetric and gravimetric power density to be applied to portable and transportation fields. However, reducing the thickness of the metal substrate, which generally occupies the most portion of the volume and mass among components of the MS-SOFC, may cause mechanical deformation during fabrication processes. In this study, mechanical behavior of the MS-SOFC, especially consists of a thin metal substrate (~100 µm) and thin-film electrolyte deposited through wet chemical coating processes, was addressed. First of all, thermal surface stress generated during the wet chemical coating processes and mechanical deformation caused by the thermal surface stress were measured by thermomechanical analysis and surface profiler, respectively. Furthermore, after quantifying the mechanical deformation of the MS-SOFC, a novel method of introducing magnets in the wet chemical coating processes to suppress mechanical deformation was proposed and evaluated. As a result, vertical deformation of the MS-SOFC was successfully suppressed from approximately 160 µm to 30 µm without significant defects of the electrolyte such as cracks, pinholes or residual stresses.