An electronic circuit component mounter, including: a substrate holding device to hold a circuit substrate; a component supply device (23, 24) to supply electronic circuit components; a mounting device including (a) a component holding tool, (b) a movable member to hold the component holding tool, and (c) a moving device to move at least the movable member relative to the substrate holding device; and a control device to control the mounting device so that electronic circuit components are received by the component holding tool from the component supply device (23, 24) and mounted on the circuit substrate held by the substrate holding device, wherein the component supply device (23, 24) includes a moving type component supply device which is held on the movable member and moved together with the component holding tool by the moving device and supplies electronic circuit components to that component holding tool, wherein the moving type component supply device includes at least a component storage section which stores multiple electronic circuit components, and wherein the mounting device further includes a holding tool raising/lowering device to raise/lower the component holding tool relative to the movable member, characterized in that the moving type component supply device is equipped with a detachable section which is detachable with a movable member side section which is a section on the movable member side, the detachable section includes a dropped component catch member to catch the electronic circuit components dropped from the component holding tool as dropped components in order to prevent the dropped components from dropping on a circuit substrate held by the substrate holding device, and the dropped component catch member includes an opening formed in the dropped component catch member, the opening allows the lowering of the component holding tool to a lowered position protruding below the dropped component catch member by the component tool raising/lowering device at a component mounting position. a substrate holding device to hold a circuit substrate; a component supply device (23, 24) to supply electronic circuit components; a mounting device including (a) a component holding tool, (b) a movable member to hold the component holding tool, and (c) a moving device to move at least the movable member relative to the substrate holding device; and a control device to control the mounting device so that electronic circuit components are received by the component holding tool from the component supply device (23, 24) and mounted on the circuit substrate held by the substrate holding device, wherein the component supply device (23, 24) includes a moving type component supply device which is held on the movable member and moved together with the component holding tool by the moving device and supplies electronic circuit components to that component holding tool, wherein the moving type component supply device includes at least a component storage section which stores multiple electronic circuit components, and wherein the mounting device further includes a holding tool raising/lowering device to raise/lower the component holding tool relative to the movable member, characterized in that the moving type component supply device is equipped with a detachable section which is detachable with a movable member side section which is a section on the movable member side, the detachable section includes a dropped component catch member to catch the electronic circuit components dropped from the component holding tool as dropped components in order to prevent the dropped components from dropping on a circuit substrate held by the substrate holding device, and the dropped component catch member includes an opening formed in the dropped component catch member, the opening allows the lowering of the component holding tool to a lowered position protruding below the dropped component catch member by the component tool raising/lowering device at a component mounting position.