Provided is a manufacturing method of a thin film capacitor comprising a capacitance portion in which at least one dielectric layer is sandwiched between a pair of electrode layers included in a plurality of electrode layers, the manufacturing method including a lamination process of alternately laminating the plurality of electrode layers and a dielectric film and forming a laminated body which will be the capacitance portion, a first etching process of forming an opening extending in a laminating direction with respect to the laminated body and exposing the dielectric film laminated directly on one of the plurality of electrode layers on a bottom surface of the opening, and a second etching process of exposing the one electrode layer at the bottom surface of the opening. In the second etching process, an etching rate of the one electrode layer is lower than an etching rate of the dielectric film.