A surface shape measurement device which measures a surface shape of a measurement target surface, the surface shape measurement device comprising: a detector including: a stylus supported swingably around a swing fulcrum; a sensing pin provided in a distal end portion of the stylus and extending in one direction orthogonal or oblique to a longitudinal direction of the stylus; a skid provided in a position separated from the distal end portion of the stylus in the one direction; and an urging member configured to urge the stylus toward a first rotation direction which is one of rotation directions of the stylus around the swing fulcrum and in which the sensing pin is rotated in the one direction, so as to cause a tip of the sensing pin to protrude from the skid in the one direction; a first elastic support member configured to support the detector swingably in the first rotation direction and in a second rotation direction opposite to the first rotation direction; a drive part configured to move the first elastic support member along a driving direction which is orthogonal to an axis direction of the swing fulcrum and parallel to the measurement target surface; a detector guide having a linear shape, and configured to guide the detector driven by the drive part via the first elastic support member along the measurement target surface; a guide support member having one or multiple first contact points to be brought in contact with the measurement target surface, and configured to support the detector guide in an attitude substantially parallel to the measurement target surface and at a position facing a surface of the detector opposite to a surface of the detector facing the measurement target surface; and a detector support member (26, 50) provided to the detector and configured to cause the detector guide to support the detector movably along the detector guide. a detector including: a stylus supported swingably around a swing fulcrum; a sensing pin provided in a distal end portion of the stylus and extending in one direction orthogonal or oblique to a longitudinal direction of the stylus; a skid provided in a position separated from the distal end portion of the stylus in the one direction; and an urging member configured to urge the stylus toward a first rotation direction which is one of rotation directions of the stylus around the swing fulcrum and in which the sensing pin is rotated in the one direction, so as to cause a tip of the sensing pin to protrude from the skid in the one direction; a first elastic support member configured to support the detector swingably in the first rotation direction and in a second rotation direction opposite to the first rotation direction; a drive part configured to move the first elastic support member along a driving direction which is orthogonal to an axis direction of the swing fulcrum and parallel to the measurement target surface; a detector guide having a linear shape, and configured to guide the detector driven by the drive part via the first elastic support member along the measurement target surface; a guide support member having one or multiple first contact points to be brought in contact with the measurement target surface, and configured to support the detector guide in an attitude substantially parallel to the measurement target surface and at a position facing a surface of the detector opposite to a surface of the detector facing the measurement target surface; and a detector support member (26, 50) provided to the detector and configured to cause the detector guide to support the detector movably along the detector guide.