A scroll compressor, comprising: a fixed scroll; an orbiting scroll engaging with the fixed scroll; a crankshaft having an eccentric section at an end portion for causing the orbiting scroll to carry out orbital motion; an oil supply hole penetrating an inside of the crankshaft in an axial direction and having an opening portion on an end surface of the eccentric section; an orbiting sliding bearing provided at the orbiting scroll and sliding by engaging with the eccentric section of the crankshaft; and an oil supply passage provided at an outer circumference of the eccentric section of the crankshaft so as to communicate with an end surface side and a base end side of the eccentric section; wherein the scroll compressor is structured so as to lubricate a gap between the eccentric section and the orbiting sliding bearing by lubricating oil supplied through the oil supply hole, characterized in that the scroll compressor further comprises: an axial loss reduction groove provided at the outer circumference of the eccentric section of the crankshaft separately from the oil supply passage; and a seal section which is provided on at least one of the end surface side and the base end side of the eccentric section of the loss reduction groove; and wherein a start position of the loss reduction groove is provided at an angular position of 140° to 210° around a center of the eccentric section in a direction opposite to a rotation direction of the crankshaft, wherein 0° is set to an opposite side of an eccentricity direction of the eccentric section. a fixed scroll; an orbiting scroll engaging with the fixed scroll; a crankshaft having an eccentric section at an end portion for causing the orbiting scroll to carry out orbital motion; an oil supply hole penetrating an inside of the crankshaft in an axial direction and having an opening portion on an end surface of the eccentric section; an orbiting sliding bearing provided at the orbiting scroll and sliding by engaging with the eccentric section of the crankshaft; and an oil supply passage provided at an outer circumference of the eccentric section of the crankshaft so as to communicate with an end surface side and a base end side of the eccentric section; wherein the scroll compressor is structured so as to lubricate a gap between the eccentric section and the orbiting sliding bearing by lubricating oil supplied through the oil supply hole, characterized in that the scroll compressor further comprises: an axial loss reduction groove provided at the outer circumference of the eccentric section of the crankshaft separately from the oil supply passage; and a seal section which is provided on at least one of the end surface side and the base end side of the eccentric section of the loss reduction groove; and wherein a start position of the loss reduction groove is provided at an angular position of 140° to 210° around a center of the eccentric section in a direction opposite to a rotation direction of the crankshaft, wherein 0° is set to an opposite side of an eccentricity direction of the eccentric section. an axial loss reduction groove provided at the outer circumference of the eccentric section of the crankshaft separately from the oil supply passage; and a seal section which is provided on at least one of the end surface side and the base end side of the eccentric section of the loss reduction groove; and wherein a start position of the loss reduction groove is provided at an angular position of 140° to 210° around a center of the eccentric section in a direction opposite to a rotation direction of the crankshaft, wherein 0° is set to an opposite side of an eccentricity direction of the eccentric section.