A driving unit for a vehicle, the driving unit comprising: a rotary electric machine which has a rotation axis extending in a horizontal direction when the driving unit is mounted on the vehicle, and which has a substantially cylindrical shape; a rotary electric machine case which has a rotary electric machine accommodating portion accommodating the rotary electric machine; and an electric power conversion device which is electrically connected to the rotary electric machine and converts electric power supplied to the rotary electric machine and electric power supplied from the rotary electric machine, and which has a substantially rectangular parallelepiped shape, wherein: the electric power conversion device is disposed on one side of the rotary electric machine in an orthogonal direction orthogonal to both a rotation axis direction and an up-down direction when the driving unit is mounted on the vehicle; a space (S1, S2) is formed between an end portion of the rotary electric machine on the one side and a surface of the electric power conversion device on an other side in the orthogonal direction; a first connecting portion electrically connecting the rotary electric machine and the electric power conversion device is disposed below the rotation axis when the driving unit is mounted on the vehicle; a second connecting portion electrically connecting a sensor provided to the rotary electric machine and the electric power conversion device is disposed above the rotation axis when the driving unit is mounted on the vehicle; and characterized in that the first connecting portion and the second connecting portion are disposed in the space (S 1, S2) between the rotary electric machine and the electric power conversion device in the orthogonal direction when viewed from the rotation axis direction. a rotary electric machine which has a rotation axis extending in a horizontal direction when the driving unit is mounted on the vehicle, and which has a substantially cylindrical shape; a rotary electric machine case which has a rotary electric machine accommodating portion accommodating the rotary electric machine; and an electric power conversion device which is electrically connected to the rotary electric machine and converts electric power supplied to the rotary electric machine and electric power supplied from the rotary electric machine, and which has a substantially rectangular parallelepiped shape, wherein: the electric power conversion device is disposed on one side of the rotary electric machine in an orthogonal direction orthogonal to both a rotation axis direction and an up-down direction when the driving unit is mounted on the vehicle; a space (S1, S2) is formed between an end portion of the rotary electric machine on the one side and a surface of the electric power conversion device on an other side in the orthogonal direction; a first connecting portion electrically connecting the rotary electric machine and the electric power conversion device is disposed below the rotation axis when the driving unit is mounted on the vehicle; a second connecting portion electrically connecting a sensor provided to the rotary electric machine and the electric power conversion device is disposed above the rotation axis when the driving unit is mounted on the vehicle; and characterized in that the first connecting portion and the second connecting portion are disposed in the space (S 1, S2) between the rotary electric machine and the electric power conversion device in the orthogonal direction when viewed from the rotation axis direction. the electric power conversion device is disposed on one side of the rotary electric machine in an orthogonal direction orthogonal to both a rotation axis direction and an up-down direction when the driving unit is mounted on the vehicle; a space (S1, S2) is formed between an end portion of the rotary electric machine on the one side and a surface of the electric power conversion device on an other side in the orthogonal direction; a first connecting portion electrically connecting the rotary electric machine and the electric power conversion device is disposed below the rotation axis when the driving unit is mounted on the vehicle; a second connecting portion electrically connecting a sensor provided to the rotary electric machine and the electric power conversion device is disposed above the rotation axis when the driving unit is mounted on the vehicle; and characterized in that the first connecting portion and the second connecting portion are disposed in the space (S 1, S2) between the rotary electric machine and the electric power conversion device in the orthogonal direction when viewed from the rotation axis direction.