ELECTROLYTE SHEET FOR SOLID OXIDE FUEL CELL, METHOD FOR MANUFACTURING ELECTROLYTE SHEET FOR SOLID OXIDE FUEL CELL, AND UNIT CELL FOR SOLID OXIDE FUEL CELL

An electrolyte sheet for solid oxide fuel cells includes a ceramic plate body having rounded corners in a plan view from a thickness direction of the ceramic plate body, the ceramic plate body having a thickness of 200 μm or less, and each of the rounded corners having a ratio Dmax/Dmin of 1.0 to 1.1, wherein Dmax and Dmin respectively represent maximum and minimum values between distances D from an intersection of extension lines of two sides of the ceramic plate body adjacent to a respective corner to starting points of the respective extension lines in the plan view.