To carry out energy saving and space saving by differentiating a driving motor and a transmission member according to momentum of each heald frame in the electric opening device of a loom.

This electric opening apparatus of loom is constituted so that a plurality of heald frames 2 are each independently driven by a driving motor 3 and transmission members (a swing rod 6, a driving lever 7 and a connecting rod 8). In the electric opening apparatus, at least the heald frame 2 on cloth fell side and the heald frame 2 on feed out side are driven by each using driving motors 3 having different rated power and the rated power of the driving motor 3 driving the heald frame 2 on the side having small momentum is made small, compared with the rated power of the driving motor 3 driving the heald frame 2 on the side having large momentum, and in at least the heald frame 2 on cloth fell and the heald frame 2 on feed out side, transmission members (6, 7 and 8) having different stiffness are used and the stiffness of transmission members (6, 7 and 8) driving the heald frame 2 on the side having small momentum is made small, compared with the stiffness of transmission members (6, 7 and 8) driving the heald frame 2 on the side having large momentum.