A bonding apparatus 10 having a diagonal optical system 30, the bonding apparatus moves a capillary 24 down to a first heightwise position to calculate a position A11 of a tip end portion of the capillary 24 and a position A12 of a tip end portion of the capillary in an image on an imaging plane of the diagonal optical system 30, and similarly moves the capillary 24 down to a further lower second heightwise position to calculate a position A21 of the tip end portion of the capillary 24 and a position A22 of the tip end portion of the capillary in the image on the imaging plane. The bonding apparatus then estimates the position of the landing point of the capillary 24 on a bonding target 8 based on positional data for the four calculated positions A11, A12, A21, and A22, the first heightwise position, and the second heightwise position. With this, it is possible to use the diagonal optical system in the bonding apparatus to further improve positional accuracy in the bonding process.