A bag supply system comprising: a bag accommodating unit having a holding member to externally support a bag bundle; a moving unit that is configured to move the bag accommodating unit to a bag bundle replenishment position where the bag bundle is supplied to the bag accommodating unit and a bag bundle supply position where the bag bundle is taken out of the bag accommodating unit; and a bag supply device to which a plurality of bags are supplied from the bag accommodating unit arranged at the bag bundle supply position, wherein: the bag supply device includes: a taking-out unit that is configured to take the bag bundle out of the bag accommodating unit and to carry the bag bundle to a depositing unit; a bag transporting unit that is configured to transport the bag bundle from the depositing unit to accommodate the bag bundle in a magazine; and a first bag pickup unit that is configured to take out two or more bags included in the bag bundle accommodated in the magazine one by one, the holding member is configured to support the bag bundle in a state of exposing a part of one of a front surface and a back surface of each of a bag arranged on a frontmost side and a bag arranged on a backmost side of the two or more bags included in the bag bundle, and the taking-out unit is configured to take the bag bundle out of the bag accommodating unit while holding the exposed part of the bag bundle supported by the holding member. a bag accommodating unit having a holding member to externally support a bag bundle; a moving unit that is configured to move the bag accommodating unit to a bag bundle replenishment position where the bag bundle is supplied to the bag accommodating unit and a bag bundle supply position where the bag bundle is taken out of the bag accommodating unit; and a bag supply device to which a plurality of bags are supplied from the bag accommodating unit arranged at the bag bundle supply position, wherein: the bag supply device includes: a taking-out unit that is configured to take the bag bundle out of the bag accommodating unit and to carry the bag bundle to a depositing unit; a bag transporting unit that is configured to transport the bag bundle from the depositing unit to accommodate the bag bundle in a magazine; and a first bag pickup unit that is configured to take out two or more bags included in the bag bundle accommodated in the magazine one by one, the holding member is configured to support the bag bundle in a state of exposing a part of one of a front surface and a back surface of each of a bag arranged on a frontmost side and a bag arranged on a backmost side of the two or more bags included in the bag bundle, and the taking-out unit is configured to take the bag bundle out of the bag accommodating unit while holding the exposed part of the bag bundle supported by the holding member. a taking-out unit that is configured to take the bag bundle out of the bag accommodating unit and to carry the bag bundle to a depositing unit; a bag transporting unit that is configured to transport the bag bundle from the depositing unit to accommodate the bag bundle in a magazine; and a first bag pickup unit that is configured to take out two or more bags included in the bag bundle accommodated in the magazine one by one, the holding member is configured to support the bag bundle in a state of exposing a part of one of a front surface and a back surface of each of a bag arranged on a frontmost side and a bag arranged on a backmost side of the two or more bags included in the bag bundle, and the taking-out unit is configured to take the bag bundle out of the bag accommodating unit while holding the exposed part of the bag bundle supported by the holding member.