A component mounting device moves a board height sensor horizontally to multiple measuring points and measures heights of the front surface of the board at the multiple measuring points. Subsequently, the component mounting device obtains a positional deviation in the horizontal direction of a target mounting position on the front surface of the board based on the heights of the front surface of the board so measured. In addition, the component mounting device obtains a positional deviation in a vertical direction of the target mounting position based on a measured height in the vertical direction of the front surface of the board. Then, the component mounting device corrects the target mounting position based on the positional deviation in the horizontal direction and the positional deviation in the vertical direction that are so obtained and mounts a component in the target mounting position so corrected.