An all-solid battery having a high output power is provided which exhibits high safety and is capable of being produced at a low cost is provided. The all-solid battery includes an internal electrode body having a cathode comprising a cathode material, an anode comprising an anode material, and a solid electrolyte layer comprising a solid electrolyte. The cathode material, the anode material, and the solid electrolyte are phosphoric acid compounds. The internal electrode body is integrated by firing the cathode, the anode, and the solid electrolyte layer, and the internal electrode body contains water.