To provide a work gripping device of a robot by reciprocative turning without a problem of dust, etc.

This work gripping device is formed at a central part of a prismatic frame 1 so that a driving gear shaft 6 can rotate, and gears 8A, 8B, 8C engaged with a gear 7 mounted on a lower part of the driving gear shaft 6 of the prismatic frame 1 are arranged with three equal intervals between each other on a lower surface part. A lower cover 10 formed to insert shield type bearings 15A, 15B, 15C and dust-tight seals 16A, 16B, 16C in pivots 9A, 9B, 9C mounted on the gears 8A, 8B, 8C are mounted on the prismatic frame 1 with a screw, the pivots 9A, 9B, 9C are projected from a lower surface of the lower cover 10, arms 11A, 11B, 11C on which fingers 12A, 12B, 12C are fastened are mounted on lower parts of the pivots 9A, 9B, 9C and the driving gear shaft 6 is reciprocatively rotated. Consequently, the fingers 12A, 12B, 12C simultaneously turn, and hold and release a work 50.