To provide a method of manufacturing an integrated thin-film solar cell in which a non-effective area of the cell is reduced, which eliminates the need for turning over or cleaning of a substrate, and which does not expose the substrate to an atmosphere.

The method of manufacturing an integrated thin-film solar cell includes: a step of preparing a substrate on which trenches are separately formed at given intervals; a step of forming a first electrode layer on a portion of the bottom and one side face of each of the trenches using a first conductive material; a step of forming a solar cell layer on the first electrode layer and on a portion of the trench on which the first electrode layer is not formed; a step of obliquely vapor-depositing a second conductive material on the solar cell layer to form a second electrode layer; a step of etching the solar cell layer formed on the trenches such that the first electrode layer may be exposed; and a step of obliquely vapor-depositing a third conductive material on the second electrode layer to form a conductive layer such that the exposed first electrode layer and the second electrode layer may be electrically interconnected.