A solid electrolyte and a method of manufacturing the same are provided. The solid electrolyte contains x atomic % of lithium, y atomic % of phosphorus, z atomic % of sulfur, and w atomic % of oxygen, in which
the x, the y, the z, and the w satisfy the following expressions (1)-(5):
20≦x≦45 (1)
10≦y≦20 (2)
35≦z≦60 (3)
1≦w≦10 (4)
x+y+z+w=100 , and (5)
apexes of X-ray diffraction peaks in an X-ray diffraction pattern obtained by an X-ray diffraction method using a Kα-ray of Cu exist at diffraction angles 2θ of 16.7°±0.25°, 20.4°±0.25°, 23.8°±0.25°, 25.9°, 0.25°, 29.4°±0.25°, 30.4°±0.25°, 31.7°±0.25°, 33.5°±0.25°, 41.5°±0.25°, 43.7°±0.25°, and 51.2°±0.25°, respectively, in the X-ray diffraction pattern, and a half-width of each of the X-ray diffraction peaks is not larger than 0.5°.