A fiber structure comprising a plurality of laminates (13, 20), wherein the laminates (13, 20) each include a plurality of stacked fiber layers (14, 24), the fiber layers (14, 24) each include reinforcement fiber yarns (11, 21), auxiliary yarns (12, 22), and intralayer structural yarns (15, 25), the reinforcement fiber yarns (11, 21) and the auxiliary yarns (12, 22) being arranged alternately, and the intralayer structural yarns (15, 25) joining the reinforcement fiber yarns (11, 21) and the auxiliary yarns (12, 22) together in an arrangement direction, in each laminate (13, 20), yarn main axis directions of the reinforcement fiber yarns (11, 21) and the auxiliary yarns (12, 22) of each of the fiber layers (14, 24) are the same, the reinforcement fiber yarns (11, 21) are arranged in such a manner that the relative positions are shifted in a stacking direction of the fiber layers (14, 24) with the reinforcement fiber yarns (11, 21) overlapping each other, the auxiliary yarns (12, 22) are arranged in such a manner that the relative positions are shifted, and the fiber layers (14, 24) are joined with intermediate structural yarns (16, 26) engaged with the auxiliary yarns (12, 22) located on opposite ends in the stacking direction, characterised in that the laminates (13, 20) are arranged such that a yarn main axis of the reinforcement fiber yarns (11, 21) of each laminate (13, 20) is orthogonal to a yarn main axis of the reinforcement fiber yarns (11, 21) of another laminate (13, 20), and a yarn main axis of the auxiliary yarns (12, 22) of each laminate (13, 20) is orthogonal to a yarn main axis of the auxiliary yarns (12, 22) of another laminate (13, 20), and the laminates (13, 20) are joined together in the stacking direction by an engagement between at least one of a set of the intralayer structural yarns (15, 25) and a set of the intermediate structural yarns (16, 26) of the laminate (13, 20) in which the yarn main axis extends in one direction and at least one of a set of the intralayer structural yarns (15, 25) and a set of the intermediate structural yarns (16, 26) of the laminate (13, 20) in which the yarn main axis extends in another direction. yarn main axis directions of the reinforcement fiber yarns (11, 21) and the auxiliary yarns (12, 22) of each of the fiber layers (14, 24) are the same, the reinforcement fiber yarns (11, 21) are arranged in such a manner that the relative positions are shifted in a stacking direction of the fiber layers (14, 24) with the reinforcement fiber yarns (11, 21) overlapping each other, the auxiliary yarns (12, 22) are arranged in such a manner that the relative positions are shifted, and the fiber layers (14, 24) are joined with intermediate structural yarns (16, 26) engaged with the auxiliary yarns (12, 22) located on opposite ends in the stacking direction, characterised in that the laminates (13, 20) are arranged such that a yarn main axis of the reinforcement fiber yarns (11, 21) of each laminate (13, 20) is orthogonal to a yarn main axis of the reinforcement fiber yarns (11, 21) of another laminate (13, 20), and a yarn main axis of the auxiliary yarns (12, 22) of each laminate (13, 20) is orthogonal to a yarn main axis of the auxiliary yarns (12, 22) of another laminate (13, 20), and