In a method for manufacturing a multilayer ceramic electronic device, a multilayer ceramic element assembly is prepared that includes laminated unsintered ceramic base material layers, a first conductor pattern, a seat portion disposed in a surface of the multilayer ceramic element assembly and arranged to mount a surface mount electronic device thereon, a second conductor pattern connected to the surface mount electronic device, and a resin introduction portion located outside a vertically projected region of the surface mount electronic device and arranged to introduce a resin to the seat portion. The multilayer ceramic element assembly is fired and the surface mount electronic device is mounted on the seat portion of the fired multilayer ceramic element assembly with the second conductor pattern therebetween. The resin is filled from the resin introduction portion into the seat portion and between the seat portion and the surface mount electronic device, and the resin is cured.