Solid-state secondary battery

A solid-state secondary battery comprising:

• a positive electrode layer including a positive electrode current collector layer and a positive electrode active material layer;
• a negative electrode layer including a negative electrode current collector layer and a negative electrode active material layer;
• a solid-state electrolyte layer including a solid-state electrolyte;
• and
• side margin layers arranged side by side on outer circumferences of the positive electrode layer and the negative electrode layer,
• wherein the solid-state secondary battery is made of a laminated body obtained by alternately laminating the positive electrode layer of which the side margin layer arranged on the outer circumference thereof and the negative electrode layer of which the side margin layer arranged on the outer circumference thereof with the solid-state electrolyte layer arranged therebetween, and
• when the porosity of the side margin layers is defined as φm and the porosity of the solid-state electrolyte layer is defined as φe, a porosity ratio (φm/φe) satisfies the following Expression (1);
• 0.5≤(φm/φe)<1.0 (1).