A method of manufacturing a shell-type transformer, the method comprising: stacking a plurality of electromagnetic steel plates and forming an E-shaped stacked body having an E shape as seen in a stacking direction of the plurality of electromagnetic steel plates , the E-shaped stacked body including a lower yoke iron core and three leg iron cores that are vertical to the lower yoke iron core ; pressing the E-shaped stacked body for integration from both sides in the stacking direction, and forming an E-shaped iron core ; rotating the E-shaped iron core such that the lower yoke iron core is located on a lower side; placing the E-shaped iron core so as to be housed in a tank main body in a state where the lower yoke iron core is located on the lower side; installing a coil in the E-shaped iron core inside the tank main body such that a leg iron core located at a middle position among the three leg iron cores is inserted through the coil ; installing an upper yoke iron core in the E-shaped iron core having the coil installed therein, and forming an iron core assembly ; and attaching a cover portion to the tank main body to form a tank, and placing the iron core assembly and the coil so as to be enclosed in the tank, wherein in the rotating the E-shaped iron core , two shaft members cylindrically formed each are coaxially coupled to a position along a side edge of a corresponding one of two leg iron cores on both sides among the three leg iron cores as seen in the stacking direction, and the E-shaped iron core is rotated about the two shaft members each serving as a rotation axis. stacking a plurality of electromagnetic steel plates and forming an E-shaped stacked body having an E shape as seen in a stacking direction of the plurality of electromagnetic steel plates , the E-shaped stacked body including a lower yoke iron core and three leg iron cores that are vertical to the lower yoke iron core ; pressing the E-shaped stacked body for integration from both sides in the stacking direction, and forming an E-shaped iron core ; rotating the E-shaped iron core such that the lower yoke iron core is located on a lower side; placing the E-shaped iron core so as to be housed in a tank main body in a state where the lower yoke iron core is located on the lower side; installing a coil in the E-shaped iron core inside the tank main body such that a leg iron core located at a middle position among the three leg iron cores is inserted through the coil ; installing an upper yoke iron core in the E-shaped iron core having the coil installed therein, and forming an iron core assembly ; and attaching a cover portion to the tank main body to form a tank, and placing the iron core assembly and the coil so as to be enclosed in the tank, wherein in the rotating the E-shaped iron core , two shaft members cylindrically formed each are coaxially coupled to a position along a side edge of a corresponding one of two leg iron cores on both sides among the three leg iron cores as seen in the stacking direction, and the E-shaped iron core is rotated about the two shaft members each serving as a rotation axis. two shaft members cylindrically formed each are coaxially coupled to a position along a side edge of a corresponding one of two leg iron cores on both sides among the three leg iron cores as seen in the stacking direction, and the E-shaped iron core is rotated about the two shaft members each serving as a rotation axis. <EOS>