An operation checking device of an electronic component mounting machine that is configured to use a collecting device to collect an electronic component supplied at a component supply position of a supply device, move the collected electronic component to a board conveyed to a board conveyance position, and mount the collected electronic component at a component mounting position of the board, the operation checking device comprising: a first memory section configured to memorize an operation program of the electronic component mounting machine including at least a collection operation of the electronic component by the collecting device; characterized by: a second memory section configured to memorize shape data of the electronic component and shape data of the collecting device; a first acquiring section configured to acquire information of the electronic components and information of the collecting device based on the operation program required for a current operation memorized on the first memory section; a second acquiring section configured to acquire corresponding shape data of the electronic component and shape data of the collecting device from the second memory section based on the information of the electronic component and the information of the collecting device acquired by the first acquiring section; a processing section configured to perform processing of operation simulation of the electronic component mounting machine based on the operation program required for the current operation memorized on the first memory section, and a display section configured to acquire, at the time of collection of the electronic components by the collecting device or at a specified operation time before collection, component coordinates of the electronic component and tool coordinates of the collecting device based on the operation simulation processed by the processing section, and display in three dimensions the shape data of the electronic component and the shape data of the collecting device acquired by the second acquiring section at the acquired component coordinates and at the acquired tool coordinates. a first memory section configured to memorize an operation program of the electronic component mounting machine including at least a collection operation of the electronic component by the collecting device; characterized by: a second memory section configured to memorize shape data of the electronic component and shape data of the collecting device; a first acquiring section configured to acquire information of the electronic components and information of the collecting device based on the operation program required for a current operation memorized on the first memory section; a second acquiring section configured to acquire corresponding shape data of the electronic component and shape data of the collecting device from the second memory section based on the information of the electronic component and the information of the collecting device acquired by the first acquiring section; a processing section configured to perform processing of operation simulation of the electronic component mounting machine based on the operation program required for the current operation memorized on the first memory section, and a display section configured to acquire, at the time of collection of the electronic components by the collecting device or at a specified operation time before collection, component coordinates of the electronic component and tool coordinates of the collecting device based on the operation simulation processed by the processing section, and display in three dimensions the shape data of the electronic component and the shape data of the collecting device acquired by the second acquiring section at the acquired component coordinates and at the acquired tool coordinates. a second memory section configured to memorize shape data of the electronic component and shape data of the collecting device; a first acquiring section configured to acquire information of the electronic components and information of the collecting device based on the operation program required for a current operation memorized on the first memory section; a second acquiring section configured to acquire corresponding shape data of the electronic component and shape data of the collecting device from the second memory section based on the information of the electronic component and the information of the collecting device acquired by the first acquiring section; a processing section configured to perform processing of operation simulation of the electronic component mounting machine based on the operation program required for the current operation memorized on the first memory section, and a display section configured to acquire, at the time of collection of the electronic components by the collecting device or at a specified operation time before collection, component coordinates of the electronic component and tool coordinates of the collecting device based on the operation simulation processed by the processing section, and display in three dimensions the shape data of the electronic component and the shape data of the collecting device acquired by the second acquiring section at the acquired component coordinates and at the acquired tool coordinates.