Component mounting apparatus and component detection method

A transfer pathway of mounting heads 10 in a component-mounting round during which the mounting head 10 moves back and forth between a component feeding unit 4 and a substrate conveyance mechanism 2 is derived by a transfer pathway calculation unit 25 for each component-mounting round from mounting program data 21a. On the basis of data pertaining to the thus-derived transfer pathway, image data output from a line sensor camera assigned to a head transfer range segment that the transfer pathway of the mounting head 10 crosses in each of component-mounting rounds are selected and captured by an image selection processing unit 24. The image data output from the line sensor camera whose focusing point substantially matches the imaging target can be used for detecting whether or not a component still exists.