A bus bar comprising: a bus bar body; and a spacer provided on the bus bar body, the spacer being an insulator, wherein the bus bar body includes a first through hole portion forming a first through hole (20,22) that allows a part of a fixing member for fixing the bus bar body to be inserted therethrough; wherein the spacer includes a head portion, a body portion extending from the head portion, and a second through hole portion forming a second through hole (21,23) that allows the part of the fixing member to be inserted therethrough and is a through hole extending from the head portion to the body portion; wherein when the spacer is provided on the bus bar body, the head portion covers at least a part of a peripheral edge region of an end opening of the first through hole and the body portion covers an inner peripheral surface of the first through hole portion; wherein a surface of the spacer including an extremity of the body portion and a surface of the bus bar body are substantially in a same plane; wherein an area including the surface of the spacer and at least a part of the surface of the bus bar body is configured to contact at least a part of a surface of a heat-transfer sheet and to release heat to the heat-transfer sheet; wherein an outer peripheral surface of the body portion is fixed to the inner peripheral surface of the first through hole portion by an interface resisting movement of the spacer toward the head portion side relative to the bus bar body and in a direction away from the bus bar body; wherein at least a part of the first through hole portion of the bus bar body is formed so that a cross-sectional area of a lower end side of the body portion of the spacer can be larger than a cross-sectional area of an upper end side of the body portion of the spacer; and wherein at least a part of the body portion of the spacer is formed so that a cross-sectional area of a lower end side of the body portion of the spacer is larger than a cross-sectional area of an upper end side of the body portion of the spacer. a bus bar body; and a spacer provided on the bus bar body, the spacer being an insulator, wherein the bus bar body includes a first through hole portion forming a first through hole (20,22) that allows a part of a fixing member for fixing the bus bar body to be inserted therethrough; wherein the spacer includes a head portion, a body portion extending from the head portion, and a second through hole portion forming a second through hole (21,23) that allows the part of the fixing member to be inserted therethrough and is a through hole extending from the head portion to the body portion; wherein when the spacer is provided on the bus bar body, the head portion covers at least a part of a peripheral edge region of an end opening of the first through hole and the body portion covers an inner peripheral surface of the first through hole portion; wherein a surface of the spacer including an extremity of the body portion and a surface of the bus bar body are substantially in a same plane; wherein an area including the surface of the spacer and at least a part of the surface of the bus bar body is configured to contact at least a part of a surface of a heat-transfer sheet and to release heat to the heat-transfer sheet; wherein an outer peripheral surface of the body portion is fixed to the inner peripheral surface of the first through hole portion by an interface resisting movement of the spacer toward the head portion side relative to the bus bar body and in a direction away from the bus bar body; wherein at least a part of the first through hole portion of the bus bar body is formed so that a cross-sectional area of a lower end side of the body portion of the spacer can be larger than a cross-sectional area of an upper end side of the body portion of the spacer; and wherein at least a part of the body portion of the spacer is formed so that a cross-sectional area of a lower end side of the body portion of the spacer is larger than a cross-sectional area of an upper end side of the body portion of the spacer.