A forced air cooling-type power conversion device including power conversion circuits (20, 40) equipped with a plurality of semiconductor elements and a capacitor that stores direct-current power supply, the forced air cooling-type power conversion device converting electric power input from a power supply into an arbitrary value and outputting the electric power to a motor (60a-60d), the forced air cooling-type power conversion device comprising: - converter power conversion modules (20a-20d) and inverter power conversion modules (40a-40d) each including: a part of the semiconductor elements configuring the power conversion circuits (20, 40); - a cooler base section (27a-27d) on which the semiconductor elements are mounted; - a cooler fin section (26a-26d) provided on a rear side of a surface in the cooler base section (27a-27d) on which the semiconductor elements are mounted; - power conversion sub-blocks (75a-75d) each including: a cooler attachment member (72a-72d) to which the cooler fin sections in at least a pair of the converter or inverter power conversion modules (20a, 20b) are attached to face each other, the plurality of the cooler fin sections (26a-26d) arranged on an inner side of the cooler attachment member being collectively cooled by cooling air, and characterized by further comprising, - conductor plates (73a-73d) connected to the semiconductor elements, and a connection conductor plate (74a, 74b) that connects a plurality of the conductor plates (73a-73b), wherein a plurality of the power conversion sub-blocks (75a, 75b) configure a power conversion block (70a, 70b) with a plurality of the conductor plates (73a, 73b) arranged perpendicularly to a connection conductor plate (74a, 74b) arranged in parallel to the bottom surface of the forced air cooling-type power conversion device, and a capacitor conductor plate is connected to the capacitor, wherein the capacitor conductor plate and the connection conductor plate (74a, 74b) of the power conversion block are configured to be capable of being connected to and disconnected from each other by a conductor connection member, wherein the connection conductor plate (74a, 74b) is arranged on an upper side or a lower side of the power conversion block and arranged in a direction in which a length direction thereof is orthogonal to a direction of the cooling air, and - the power conversion blocks (70a, 70b) are configured by a set of two converter power conversion modules (20a-20d) and set of two inverter power conversion modules (40a-40d). - converter power conversion modules (20a-20d) and inverter power conversion modules (40a-40d) each including: a part of the semiconductor elements configuring the power conversion circuits (20, 40); - a cooler base section (27a-27d) on which the semiconductor elements are mounted; - a cooler fin section (26a-26d) provided on a rear side of a surface in the cooler base section (27a-27d) on which the semiconductor elements are mounted; - power conversion sub-blocks (75a-75d) each including: a cooler attachment member (72a-72d) to which the cooler fin sections in at least a pair of the converter or inverter power conversion modules (20a, 20b) are attached to face each other, the plurality of the cooler fin sections (26a-26d) arranged on an inner side of the cooler attachment member being collectively cooled by cooling air, and characterized by further comprising, - conductor plates (73a-73d) connected to the semiconductor elements, and a connection conductor plate (74a, 74b) that connects a plurality of the conductor plates (73a-73b), - the power conversion blocks (70a, 70b) are configured by a set of two converter power conversion modules (20a-20d) and set of two inverter power conversion modules (40a-40d).