To provide an electrode composite material capable of exhibiting a high battery capability, containing a particular crystalline sulfide solid electrolyte and an electrode active material, and a method for producing an electrode composite material, including; firstly mixing a raw material inclusion containing at least one kind of a lithium element, a sulfur element, and a phosphorus element, with a complexing agent, so as to form an electrolyte precursor; heating to decomplex the electrolyte precursor; and secondly mixing a decomplexed material obtained through the decomplexing, with an electrode active material.