Bonding apparatus and method for detecting height of bonding target

A bonding apparatus having an optical system, an imaging element for acquiring an image formed by the optical system as a picture, an illumination unit for illuminating an electronic component, and a control part for processing the image acquired by the imaging element, the control part illuminating the electronic component through a first inclined optical path inclined with respect to the optical axis of a first portion of the optical system facing the electronic component and acquiring a first image, illuminating the electronic component through a second inclined optical path inclined toward the opposite side from the first inclined optical path with respect to the optical axis and acquiring a second image of the electronic component as a subject, and calculating an amount of variation from a reference height of the electronic component on the basis of the positional offset amount between the first image and the second image.