To provide a structure of a loom by which the durability of a heald is improved.

This loom of bringing an opening movement to the heald 1 through upper and lower heald bars 2 and 3 fixed to a heald frame 7 has relations between the largeness (a) of spaces between the heald 1 and the heald bars 2 and 3 in the upper and lower direction, and the largeness (b) of a space between the lower heald bar 3 and a lower heald loop 5 of the heald 1 engaging therewith in the upper and lower direction, satisfying the following conditions: 0≤(b)-(a)≤0.0038×L; (a)=A-B; and (b)=C-D (wherein, L is the length from the upper end part 4a of the upper heald loop of the heald 1 to the upper end part 5a of the lower heald loop of the heald 1; A is the length from the upper end part 4a of the upper heald loop of the heald 1 to the lower end part 5b of the lower heald loop; B is the length from the upper end part of the upper heald bar 2 to the lower end part of the lower heald bar 3; C is the length of the lower heald loop 5 in the upper and lower direction; and D is the length of the lower heald bar 3 in the upper and lower direction).