A switching element unit comprising: a switching element set that forms an inverter circuit; a first bus bar configured to be connectable to one of a positive electrode and a negative electrode of a DC power supply; a second bus bar configured to be connectable to another of the positive electrode and the negative electrode of the DC power supply; an output bus bar configured to be connectable to an AC device; and a molded portion; wherein the switching element set includes a first switching element connected to the first bus bar and the output bus bar, and a second switching element connected to the second bus bar and the output bus bar; wherein the first switching element and the second switching element are arranged side by side in a first direction; wherein the output bus bar is disposed to extend in the first direction while being in contact with a surface of the first switching element opposite to a surface in contact with the first bus bar, and being in contact with a surface of the second switching element opposite to a surface in contact with the second bus bar; wherein the first switching element and the second switching element are disposed to be embedded in the molded portion; and wherein the output bus bar includes an embedded portion embedded in the molded portion, a first exposed portion exposed from the molded portion on one side of the switching element set in the first direction, and a second exposed portion exposed from the molded portion on another side of the switching element set in the first direction, wherein the first switching element and the second switching element are located in a common reference plane; wherein one side in an orthogonal direction orthogonal to the reference plane is defined as a first side, and a side opposite to the first side in the orthogonal direction is defined as a second side; characterised in that the output bus bar includes, sequentially from one side in an extending direction of the output bus bar, a first extending portion, a first joining portion in contact with a surface on the first side of the first switching element, a second joining portion in contact with a surface on the second side of the second switching element, and a second extending portion; wherein the first extending portion includes a first part extending in the first direction from the first joining portion, and a second part extending from an end of the first part on a side opposite to the first joining portion to the second side; wherein the second extending portion includes a third part extending in the first direction from the second joining portion; wherein a region of the second part exposed from the molded portion to the second side defines the first exposed portion; and wherein a region of the third part exposed from the molded portion to the second side defines the second exposed portion. a switching element set that forms an inverter circuit; a first bus bar configured to be connectable to one of a positive electrode and a negative electrode of a DC power supply; a second bus bar configured to be connectable to another of the positive electrode and the negative electrode of the DC power supply; an output bus bar configured to be connectable to an AC device; and a molded portion; wherein the switching element set includes a first switching element connected to the first bus bar and the output bus bar, and a second switching element connected to the second bus bar and the output bus bar; wherein the first switching element and the second switching element are arranged side by side in a first direction; wherein the output bus bar is disposed to extend in the first direction while being in contact with a surface of the first switching element opposite to a surface in contact with the first bus bar, and being in contact with a surface of the second switching element opposite to a surface in contact with the second bus bar; wherein the first switching element and the second switching element are disposed to be embedded in the molded portion; and wherein the output bus bar includes an embedded portion embedded in the molded portion, a first exposed portion exposed from the molded portion on one side of the switching element set in the first direction, and a second exposed portion exposed from the molded portion on another side of the switching element set in the first direction, wherein the first switching element and the second switching element are located in a common reference plane; wherein one side in an orthogonal direction orthogonal to the reference plane is defined as a first side, and a side opposite to the first side in the orthogonal direction is defined as a second side; characterised in that the output bus bar includes, sequentially from one side in an extending direction of the output bus bar, a first extending portion, a first joining portion in contact with a surface on the first side of the first switching element, a second joining portion in contact with a surface on the second side of the second switching element, and a second extending portion; wherein the first extending portion includes a first part extending in the first direction from the first joining portion, and a second part extending from an end of the first part on a side opposite to the first joining portion to the second side; wherein the second extending portion includes a third part extending in the first direction from the second joining portion; wherein a region of the second part exposed from the molded portion to the second side defines the first exposed portion; and wherein a region of the third part exposed from the molded portion to the second side defines the second exposed portion.