An assembly method for a shafting of a power generating apparatus of a renewable energy type, the power generating apparatus of a renewable energy type including: at least one blade; a hub to which the at least one blade is attached; a rotation shaft coupled to the hub; and a first bearing and a second bearing which support the rotation shaft, the method comprising: a step of placing the rotation shaft to stand upright along a vertical direction; a step of moving the first bearing relative to the rotation shaft to a first mounting position so that the rotation shaft standing upright is inserted into the first bearing which is a thrust free bearing; a step of holding the first bearing at the first mounting position by supporting the first bearing from below; a step of mounting the first bearing to the rotation shaft in a state where the first bearing is held at the first mounting position; a step of fixing a lower end of a spacer to the first bearing so that the spacer extends upward from the first bearing in a state where the first bearing is held at the first mounting position; a step of moving the second bearing relative to the rotation shaft to a second mounting position so that the rotation shaft standing upright is inserted into the second bearing and the second bearing contacts an upper end of the spacer; a step of fixing the second bearing to the upper end of the spacer; and a step of mounting the second bearing to the rotation shaft in a state where the second bearing is fixed to the upper end of the spacer. at least one blade; a hub to which the at least one blade is attached; a rotation shaft coupled to the hub; and a first bearing and a second bearing which support the rotation shaft, the method comprising: a step of placing the rotation shaft to stand upright along a vertical direction; a step of moving the first bearing relative to the rotation shaft to a first mounting position so that the rotation shaft standing upright is inserted into the first bearing which is a thrust free bearing; a step of holding the first bearing at the first mounting position by supporting the first bearing from below; a step of mounting the first bearing to the rotation shaft in a state where the first bearing is held at the first mounting position; a step of fixing a lower end of a spacer to the first bearing so that the spacer extends upward from the first bearing in a state where the first bearing is held at the first mounting position; a step of moving the second bearing relative to the rotation shaft to a second mounting position so that the rotation shaft standing upright is inserted into the second bearing and the second bearing contacts an upper end of the spacer; a step of fixing the second bearing to the upper end of the spacer; and a step of mounting the second bearing to the rotation shaft in a state where the second bearing is fixed to the upper end of the spacer. a step of placing the rotation shaft to stand upright along a vertical direction; a step of moving the first bearing relative to the rotation shaft to a first mounting position so that the rotation shaft standing upright is inserted into the first bearing which is a thrust free bearing; a step of holding the first bearing at the first mounting position by supporting the first bearing from below; a step of mounting the first bearing to the rotation shaft in a state where the first bearing is held at the first mounting position; a step of fixing a lower end of a spacer to the first bearing so that the spacer extends upward from the first bearing in a state where the first bearing is held at the first mounting position; a step of moving the second bearing relative to the rotation shaft to a second mounting position so that the rotation shaft standing upright is inserted into the second bearing and the second bearing contacts an upper end of the spacer; a step of fixing the second bearing to the upper end of the spacer; and a step of mounting the second bearing to the rotation shaft in a state where the second bearing is fixed to the upper end of the spacer.