A component mounting apparatus, comprising: a controller for overall control of the component mounting apparatus; an operational sequence supervision unit determining an operational sequence specifying a series of standard sequence operations of suctioning, recognizing and mounting a component, a first memory unit which stores component data relating to a component to be suctioned and mounted, and mounting data designating coordinates on a board where a component is to be mounted; and a mounting unit which mounts a component on a board that has been conveyed into the apparatus and then conveys the board out from the apparatus by using component data and mounting data stored in the first memory unit, by executing an operational sequence determined by the operational sequence supervision unit; characterised by the operational sequence supervision unit allowing to carry out a special interpreter language processing execution routine, which is a routine for causing the component mounting apparatus to execute a custom program, written in interpreter language and specifying an operation different to the series of the standard sequence operations; a second memory unit which stores the custom program and custom program designation information that designates execution of the custom program; and wherein the operational sequence supervision unit which is created in compiler language, controls a sequence for causing the component mounting apparatus to repeatedly carry out the standard sequence operations and a switching process for switching from the series of standard sequence operations to the special interpreter language processing execution routine for executing the custom program, during, or before or after, the series of standard sequence operations in accordance with the custom program designation information; and the mounting unit executes an operation specified by the custom program in accordance with the custom program designation information, during, or before or after, sequence operations of suctioning, recognizing and mounting a component as determined by the operational sequence supervision unit. a controller for overall control of the component mounting apparatus; an operational sequence supervision unit determining an operational sequence specifying a series of standard sequence operations of suctioning, recognizing and mounting a component, a first memory unit which stores component data relating to a component to be suctioned and mounted, and mounting data designating coordinates on a board where a component is to be mounted; and a mounting unit which mounts a component on a board that has been conveyed into the apparatus and then conveys the board out from the apparatus by using component data and mounting data stored in the first memory unit, by executing an operational sequence determined by the operational sequence supervision unit; characterised by the operational sequence supervision unit allowing to carry out a special interpreter language processing execution routine, which is a routine for causing the component mounting apparatus to execute a custom program, written in interpreter language and specifying an operation different to the series of the standard sequence operations; a second memory unit which stores the custom program and custom program designation information that designates execution of the custom program; and wherein the operational sequence supervision unit which is created in compiler language, controls a sequence for causing the component mounting apparatus to repeatedly carry out the standard sequence operations and a switching process for switching from the series of standard sequence operations to the special interpreter language processing execution routine for executing the custom program, during, or before or after, the series of standard sequence operations in accordance with the custom program designation information; and the mounting unit executes an operation specified by the custom program in accordance with the custom program designation information, during, or before or after, sequence operations of suctioning, recognizing and mounting a component as determined by the operational sequence supervision unit.