In an electronic component mounting apparatus, a vertical load and horizontal loads applied to an electronic component are detected by a load sensor that has piezoelectric elements provided in a stack in a mounting direction of the electronic component. Therefore, a size in a horizontal direction of the load sensor can be reduced, and a load applied to the electronic component can be detected at a neighborhood of a mounting position of the electronic component. Moreover, by comparing a position, in a two-dimensional space in which load values in an X-direction and Y-direction of the horizontal load serve as coordinate values, with a tolerance range in the two-dimensional space, a mounting failure can be detected from a deviation in the horizontal loads.