An end effector device comprising: a hand having a storing space; and a plurality of holding portions (4A, 4B) provided to the hand and configured to hold parts of each of a plurality of plate members so as to hold the plurality of plate members respectively, the parts being different from each other in a peripheral direction of a peripheral edge portion of each plate member respectively, wherein each of the holding portions (4A, 4B) includes a plurality of receiving portions which respectively receive peripheral edge portions of the plurality of plate members so that the plurality of plate members are arranged substantially parallel with one plane and at an interval or intervals mutually in a first direction which is substantially perpendicular to the one plane, and a pitch changing mechanism configured to linearly move the plurality of receiving portions in the first direction respectively so as to change the interval or intervals, wherein a plurality of linearly moving portions (41A, 41B) configured to respectively move linearly integrally with the plurality of receiving portions of the pitch changing mechanism are provided to the hand so as to be exposed outside of the hand, wherein a plurality of drive portions (8A to 8D) configured to drive the plurality of linearly moving portions (41A, 41B) of the pitch changing mechanism respectively are stored in the storing space of the hand, wherein the hand includes a hollow body portion formed so as to extend in a second direction substantially parallel with the one plane, and a hollow movable portion connected to a proximal end portion of the body portion so as to be capable of advancing and retreating in the second direction, and wherein the plurality of holding portions (4A, 4B) include first holding portions provided to a distal end portion of the body portion and second holding portions provided to the movable portion. a hand having a storing space; and a plurality of holding portions (4A, 4B) provided to the hand and configured to hold parts of each of a plurality of plate members so as to hold the plurality of plate members respectively, the parts being different from each other in a peripheral direction of a peripheral edge portion of each plate member respectively, wherein each of the holding portions (4A, 4B) includes a plurality of receiving portions which respectively receive peripheral edge portions of the plurality of plate members so that the plurality of plate members are arranged substantially parallel with one plane and at an interval or intervals mutually in a first direction which is substantially perpendicular to the one plane, and a pitch changing mechanism configured to linearly move the plurality of receiving portions in the first direction respectively so as to change the interval or intervals, wherein a plurality of linearly moving portions (41A, 41B) configured to respectively move linearly integrally with the plurality of receiving portions of the pitch changing mechanism are provided to the hand so as to be exposed outside of the hand, wherein a plurality of drive portions (8A to 8D) configured to drive the plurality of linearly moving portions (41A, 41B) of the pitch changing mechanism respectively are stored in the storing space of the hand, wherein the hand includes a hollow body portion formed so as to extend in a second direction substantially parallel with the one plane, and a hollow movable portion connected to a proximal end portion of the body portion so as to be capable of advancing and retreating in the second direction, and wherein the plurality of holding portions (4A, 4B) include first holding portions provided to a distal end portion of the body portion and second holding portions provided to the movable portion.