A load cell includes a flexural element in which a Roberval mechanism is formed by a pair of top and bottom parallel beams each including two thin sections at a back and a front in a longitudinal direction, which are integrated with a fixed portion and a movable portion, and strain gauges bonded to the thin sections. Strain gauges are bonded to one of the thin sections of pulling side and to one of the thin sections of compressing side, and circular apertures are formed through the remaining two thin sections. The performances of the load cell such as the reduction of the measurement error and of the period of time before the start of the measurement are achieved.