A manufacturing method for an electronic apparatus, wherein the method comprises: preparing a first printed board having a first main surface and a second main surface opposite to the first main surface, the first printed board having, on the first main surface, a plurality of first connection land portions provided along a side end of the first printed board, a cutout portion being provided between the plurality of first connection land portions; preparing a second printed board having a third main surface and a fourth main surface opposite to the third main surface, the second printed board having, on the fourth main surface, a plurality of second connection land portions provided along a side end of the second printed board, a cutout portion being provided between the plurality of second connection land portions; joining the first printed board and the second printed board together with a conductive joining material such that the first main surface is opposed to the fourth main surface and the plurality of first connection land portions are electrically connected to the corresponding second connection land portions; preparing a case which is upwardly open and which has a first bottom surface and a second bottom surface disposed deeper than the first bottom surface; storing the joined first and second printed boards (10, 20) in the case such that the second main surface of the first printed board is in contact with the first bottom surface and the second printed board is located above the second bottom surface; closing the opening in the upper portion of the case with a cover plate; and sealing the first and second printed boards (10, 20) stored in the case by injecting a sealing resin into a storage space defined by the case and the cover plate, characterized in that in the joining, the first printed board and the second printed board are joined together such that the cutout portion of the first printed board and the cutout portion of the second printed board at least partially overlap with each other to form a penetrating hole, in the storing, the joined first and second printed boards (10, 20) are stored in the case such that the penetrating hole communicates with a space defined by the case and the second printed board and at least a part of the penetrating hole is located above an inclined surface connecting the first bottom surface and the second bottom surface, and in the sealing, after the case is arranged such that an opening in a side surface of the case is oriented upward, the sealing resin is injected into the space through the opening in the side surface, thereby moving air bubbles retained in the space upward along the inclined surface to release the air bubbles to the first main surface side of the first printed board through the penetrating hole. preparing a first printed board having a first main surface and a second main surface opposite to the first main surface, the first printed board having, on the first main surface, a plurality of first connection land portions provided along a side end of the first printed board, a cutout portion being provided between the plurality of first connection land portions; preparing a second printed board having a third main surface and a fourth main surface opposite to the third main surface, the second printed board having, on the fourth main surface, a plurality of second connection land portions provided along a side end of the second printed board, a cutout portion being provided between the plurality of second connection land portions; joining the first printed board and the second printed board together with a conductive joining material such that the first main surface is opposed to the fourth main surface and the plurality of first connection land portions are electrically connected to the corresponding second connection land portions; preparing a case which is upwardly open and which has a first bottom surface and a second bottom surface disposed deeper than the first bottom surface; storing the joined first and second printed boards (10, 20) in the case such that the second main surface of the first printed board is in contact with the first bottom surface and the second printed board is located above the second bottom surface; closing the opening in the upper portion of the case with a cover plate; and sealing the first and second printed boards (10, 20) stored in the case by injecting a sealing resin into a storage space defined by the case and the cover plate, characterized in that in the joining, the first printed board and the second printed board are joined together such that the cutout portion of the first printed board and the cutout portion of the second printed board at least partially overlap with each other to form a penetrating hole, in the storing, the joined first and second printed boards (10, 20) are stored in the case such that the penetrating hole communicates with a space defined by the case and the second printed board and at least a part of the penetrating hole is located above an inclined surface connecting the first bottom surface and the second bottom surface, and in the sealing, after the case is arranged such that an opening in a side surface of the case is oriented upward, the sealing resin is injected into the space through the opening in the side surface, thereby moving air bubbles retained in the space upward along the inclined surface to release the air bubbles to the first main surface side of the first printed board through the penetrating hole.