Method for producing all solid-state battery, and all solid-state battery

An all solid-state battery comprising:

• a solid electrolyte layer;
• a first active material layer that is provided for one surface of the solid electrolyte layer;
• and
• a second active material layer that is provided for another surface of the solid electrolyte layer,
• wherein the first active material layer has an opposing part that is opposite to the second active material layer across the solid electrolyte layer, and an extending part that extends beyond the opposing part in a width direction,
• when a cross section of the first active material layer is observed, it is observed that a first active material that is included in the opposing part is constituted of a primary particle,
• wherein the relation of 0<(X1/Y)≤0.03 is satisfied wherein X1 is a diameter of the primary particle of the first active material (μm) and Y is a thickness of the solid electrolyte layer (μm),
• wherein, when the cross section of the first active material layer is observed, a number of secondary particles of the first active material which are included in the extending part per unit area is larger than a number of the secondary particles of the first active material which are included in the opposing part per unit area,
• wherein in an interfacial portion between the first active material layer and the solid electrolyte layer, only the primary particles are present, or the secondary particles and the primary particles are present, a number of the secondary particles being less than or equal to 10% of a total number of the secondary particles, and
• wherein the secondary particle of the active material is present in a portion of the first active material layer, the portion being different from the interfacial portion.