A power converter configured to be mounted on an electrically driven vehicle, comprising: a control board that controls a power module including a semiconductor device; a connector (20a, 20b) provided on the control board so as to be connected to an external controller; a first strong electric component and a second strong electric component (14, 16) arranged so as to overlap the control board; a motor control board arranged at a side of a space between the first and second strong electric components (5, 14, 16) in a direction perpendicular to the control board and in the axial direction of the motor; and a housing that houses the control board, the motor control board, and the first and the second strong electric component (5, 14, 16) therein, wherein a bottom portion of the housing is formed to swell in a convex-shaped manner, wherein a part of the first strong electric component is housed in an area of the housing that swells in the convex-shaped manner, and the first strong electric component is formed so that a projection area thereof to the control board is smaller than a surface area of the control board, and wherein the connector (20a, 20b) is arranged in an area of the control board other than a projection plane of the first strong electric component to the control board, characterized in that the second strong electric component (14, 16) is arranged in a side opposite to the first strong electric component in the axial direction of the motor with the area other than the projection plane of the first strong electric component to the control board therebetween, the connector (20a, 20b) is arranged in an area on the control board surrounded by the first and second strong electric components (5, 14, 16) and the motor control board of the area other than the projection plane of the first strong electric component to the control board, the electrically driven vehicle has a motor/generator for driving the vehicle, a cylindrical-shaped casing for the motor/generator has upwardly protruding support convex portions in both ends of the axial direction, and the power converter is introduced in upwardly protruding support convex portions, a concave portion is configured to protrude in both ends thereof in the axial direction of the motor and is hollowed in a center thereof, and the concave portion is formed on an upper surface of the motor/generator, and a portion swelling in the convex-shaped manner in the housing of the power converter is housed in the concave portion of the upper surface of the motor/generator so that the power converter is fixed to an upper portion of the motor/generator. a control board that controls a power module including a semiconductor device; a connector (20a, 20b) provided on the control board so as to be connected to an external controller; a first strong electric component and a second strong electric component (14, 16) arranged so as to overlap the control board; a motor control board arranged at a side of a space between the first and second strong electric components (5, 14, 16) in a direction perpendicular to the control board and in the axial direction of the motor; and a housing that houses the control board, the motor control board, and the first and the second strong electric component (5, 14, 16) therein, wherein a bottom portion of the housing is formed to swell in a convex-shaped manner, wherein a part of the first strong electric component is housed in an area of the housing that swells in the convex-shaped manner, and the first strong electric component is formed so that a projection area thereof to the control board is smaller than a surface area of the control board, and wherein the connector (20a, 20b) is arranged in an area of the control board other than a projection plane of the first strong electric component to the control board, characterized in that the second strong electric component (14, 16) is arranged in a side opposite to the first strong electric component in the axial direction of the motor with the area other than the projection plane of the first strong electric component to the control board therebetween, the connector (20a, 20b) is arranged in an area on the control board surrounded by the first and second strong electric components (5, 14, 16) and the motor control board of the area other than the projection plane of the first strong electric component to the control board, the electrically driven vehicle has a motor/generator for driving the vehicle, a cylindrical-shaped casing for the motor/generator has upwardly protruding support convex portions in both ends of the axial direction, and the power converter is introduced in upwardly protruding support convex portions, a concave portion is configured to protrude in both ends thereof in the axial direction of the motor and is hollowed in a center thereof, and the concave portion is formed on an upper surface of the motor/generator, and a portion swelling in the convex-shaped manner in the housing of the power converter is housed in the concave portion of the upper surface of the motor/generator so that the power converter is fixed to an upper portion of the motor/generator.