An inspection method of determining the bonded status of a wire ball bonded to a pad of a semiconductor chip is provided. An image of the bonding position between the pad and the ball is taken by an image-taking unit for detection of an in focus height of the pad, in focus height of an upper surface of the bonded ball, an external diameter of the bonded ball, and a ball bonded point respectively while switching a color of a coaxial illuminating light depending on the specific position for the inspection. Blue light can be used in the detection of the pad and an external diameter of the bonded ball while red or yellow light is used for detecting an upper surface of the bonded ball and the ball bonded point.