Abstract: A method for measuring the heights of test parts of an object to be measured and a height-measuring apparatus for carrying out the same, comprising the steps of placing an object on an X-Y table , projecting measurement light flux emitted by a light source on the object supported on the X-Y table from above the object with the measurement light flux being focused in a spot beam by an objective lens on the object, receiving the measurement light flux focused in the spot beam on and reflected from the object to be measured to cause a photosensor to detect the condition of focus on the object to be measured of the measurement light flux focused by the objective lens, moving the light source and the objective lens for horizontal scanning movement relative to the X-Y table while the objective leans is reciprocated vertically at a high speed, and determining the height of each of bonding wires on the basis of the vertical position of the objective lens when the measurement light flux is focused on the bonding wire