A component mounting system comprising: a holding tool configured to hold a component; a moving device configured to move the holding tool; an electromagnetic motor (70, 72) for lowering the holding tool in order to mount the component on a board; a detection sensor configured to detect contact of a component held by the holding tool with the board; and a control device, configured to perform a first mounting operation and a second mounting operation selectively, wherein the first mounting operation is an operation in which a component held by the holding tool is mounted on the board while executing foreign matter detection for detecting with the sensor whether there is foreign matter present at a planned mounting position, and the second mounting operation is an operation in which a component held by the holding tool is mounted on the board without executing the foreign matter detection, and wherein, in the foreign matter detection an actual component height of the component is calculated based on a detected value of an encoder of the electromagnetic motor (70, 72), a target component height is set in advance based on the height dimensions of the component and the component mounting system is configured such that, if the detection sensor detects that a member has come in contact with the component, before actual component height is lowered to target component height, it is determined that foreign matter is present at the planned mounting position on the board; wherein with respect to the mounting operation for each of the components, the control device is further configured to control the lowering speed of the holding tool so as to mount the component to the board such that the time required for the first mounting operation is longer than the time required for the second mounting operation. a holding tool configured to hold a component; a moving device configured to move the holding tool; an electromagnetic motor (70, 72) for lowering the holding tool in order to mount the component on a board; a detection sensor configured to detect contact of a component held by the holding tool with the board; and a control device, configured to perform a first mounting operation and a second mounting operation selectively, wherein the first mounting operation is an operation in which a component held by the holding tool is mounted on the board while executing foreign matter detection for detecting with the sensor whether there is foreign matter present at a planned mounting position, and the second mounting operation is an operation in which a component held by the holding tool is mounted on the board without executing the foreign matter detection, and wherein, in the foreign matter detection an actual component height of the component is calculated based on a detected value of an encoder of the electromagnetic motor (70, 72), a target component height is set in advance based on the height dimensions of the component and the component mounting system is configured such that, if the detection sensor detects that a member has come in contact with the component, before actual component height is lowered to target component height, it is determined that foreign matter is present at the planned mounting position on the board; wherein with respect to the mounting operation for each of the components, the control device is further configured to control the lowering speed of the holding tool so as to mount the component to the board such that the time required for the first mounting operation is longer than the time required for the second mounting operation.