1. A profile measuring apparatus which measures a profile of an object, comprising; an imaging element which is configured to take an image of the object on which a pattern is projected; an image formation optical system which is arranged to form an image of the pattern, projected on the object, on the imaging element and which includes an objective lens that condenses a light flux from the object on which the pattern is projected; a measuring direction changing unit which is configured to change inclination of a surface of the object with respect to the objective lens based on information of the inclination of the surface of the object so that a light flux from a point of the object, reaching the imaging element through the objective lens, enters the objective lens with an aperture angle not less than a predetermined degree; and, a measuring unit which is connected to the imaging element and measures the profile of the object based on the image, of the object on which the pattern is projected, obtained by the imaging element.