A power converting device comprising: a power module having a high-voltage main terminal, a ground main terminal, and a gate control terminal and a ground terminal for driving; and a gate driving circuit configured to drive the power module, wherein the gate driving circuit includes a first control substrate in which a signal input portion, a power input portion, a logic portion, a protection circuit portion, and a gate driving portion are mounted; and wherein a gate-wire conductor plate and a ground-wire conductor plate, which are laminated with an insulator between them to form a laminated structure, are provided between the first control substrate and the gate control terminal and the ground terminal, such that the laminated structure overlaps the gate control terminal and the ground terminal; the device being characterized in that it further comprises: a capacitor having a power terminal and a capacitor ground terminal; and main circuit wires (37, 38) configured to connect main terminals of the power module (22, 23) and terminals (32, 33) of the capacitor, respectively, wherein the insulator is also provided outside the gate-wire conductor plate and the ground-wire conductor plate to sandwich the gate wire conductor plate and the ground-wire conductor plate, wherein the laminated structure extends towards the gate control terminal and the ground terminal, the ground-wire conductor plate at the gate control terminal is removed, the gate-wire conductor plate at the ground terminal is removed, and the gate control terminal and the ground terminal are connected to respectively the gate-wire conductor plate and the ground-wire conductor plate by screws, and wherein a boss formed on the gate-wire conductor plate at the gate control terminal extends to a level which is flush with a surface of the laminated structure which is closest to the gate control terminal, and another boss formed on the ground-wire conductor plate at the ground terminal extends to the same level. a power module having a high-voltage main terminal, a ground main terminal, and a gate control terminal and a ground terminal for driving; and a gate driving circuit configured to drive the power module, wherein the gate driving circuit includes a first control substrate in which a signal input portion, a power input portion, a logic portion, a protection circuit portion, and a gate driving portion are mounted; and wherein a gate-wire conductor plate and a ground-wire conductor plate, which are laminated with an insulator between them to form a laminated structure, are provided between the first control substrate and the gate control terminal and the ground terminal, such that the laminated structure overlaps the gate control terminal and the ground terminal; the device being characterized in that it further comprises: a capacitor having a power terminal and a capacitor ground terminal; and main circuit wires (37, 38) configured to connect main terminals of the power module (22, 23) and terminals (32, 33) of the capacitor, respectively, wherein the insulator is also provided outside the gate-wire conductor plate and the ground-wire conductor plate to sandwich the gate wire conductor plate and the ground-wire conductor plate, wherein the laminated structure extends towards the gate control terminal and the ground terminal, the ground-wire conductor plate at the gate control terminal is removed, the gate-wire conductor plate at the ground terminal is removed, and the gate control terminal and the ground terminal are connected to respectively the gate-wire conductor plate and the ground-wire conductor plate by screws, and wherein a boss formed on the gate-wire conductor plate at the gate control terminal extends to a level which is flush with a surface of the laminated structure which is closest to the gate control terminal, and another boss formed on the ground-wire conductor plate at the ground terminal extends to the same level. a capacitor having a power terminal and a capacitor ground terminal; and main circuit wires (37, 38) configured to connect main terminals of the power module (22, 23) and terminals (32, 33) of the capacitor, respectively, wherein the insulator is also provided outside the gate-wire conductor plate and the ground-wire conductor plate to sandwich the gate wire conductor plate and the ground-wire conductor plate, wherein the laminated structure extends towards the gate control terminal and the ground terminal, the ground-wire conductor plate at the gate control terminal is removed, the gate-wire conductor plate at the ground terminal is removed, and the gate control terminal and the ground terminal are connected to respectively the gate-wire conductor plate and the ground-wire conductor plate by screws, and wherein a boss formed on the gate-wire conductor plate at the gate control terminal extends to a level which is flush with a surface of the laminated structure which is closest to the gate control terminal, and another boss formed on the ground-wire conductor plate at the ground terminal extends to the same level.