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 (12b, 12a, 12b) 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 (12b, 12a, 12b) 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 (20, 20a, 20b) cylindrically formed each are coaxially coupled to a position along a side edge of a corresponding one of two leg iron cores (12a, 12b) on both sides among the three leg iron cores (12b, 12a, 12b) as seen in the stacking direction, and the E-shaped iron core is rotated about the two shaft members (20, 20a, 20b) 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 (12b, 12a, 12b) 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 (12b, 12a, 12b) 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 (20, 20a, 20b) cylindrically formed each are coaxially coupled to a position along a side edge of a corresponding one of two leg iron cores (12a, 12b) on both sides among the three leg iron cores (12b, 12a, 12b) as seen in the stacking direction, and the E-shaped iron core is rotated about the two shaft members (20, 20a, 20b) each serving as a rotation axis. two shaft members (20, 20a, 20b) cylindrically formed each are coaxially coupled to a position along a side edge of a corresponding one of two leg iron cores (12a, 12b) on both sides among the three leg iron cores (12b, 12a, 12b) as seen in the stacking direction, and the E-shaped iron core is rotated about the two shaft members (20, 20a, 20b) each serving as a rotation axis.