A feedback control device comprising: a target device that is at least rotationally operated by an operation input by an operator; a first target angular velocity determining unit that determines, based on the operation input, a first target angular velocity that is a target angular velocity of an output angular velocity of the target device, using a first transfer function that is a transfer function of the target device, the first transfer function being defined by a first moment of inertia representing a moment of inertia of the target device; a control unit that determines a control input to the target device, based on a difference between the first target angular velocity and the output angular velocity; a second target angular velocity determining unit that determines, based on the operation input, a second target angular velocity that is the target angular velocity requested by the operator, the target angular velocity corresponding to the operation input; a degree of comfort determining unit that determines a degree of comfort of the operator, based on a difference between the output angular velocity and the second target angular velocity; and a database that sequentially accumulates the first target angular velocity, the degree of comfort, and a target degree of comfort, wherein the first target angular velocity determining unit adjusts the first moment of inertia in such a way as to reduce a difference between the target degree of comfort and the degree of comfort, using the first target angular velocity, the degree of comfort, and the target degree of comfort that are accumulated in the database. a target device that is at least rotationally operated by an operation input by an operator; a first target angular velocity determining unit that determines, based on the operation input, a first target angular velocity that is a target angular velocity of an output angular velocity of the target device, using a first transfer function that is a transfer function of the target device, the first transfer function being defined by a first moment of inertia representing a moment of inertia of the target device; a control unit that determines a control input to the target device, based on a difference between the first target angular velocity and the output angular velocity; a second target angular velocity determining unit that determines, based on the operation input, a second target angular velocity that is the target angular velocity requested by the operator, the target angular velocity corresponding to the operation input; a degree of comfort determining unit that determines a degree of comfort of the operator, based on a difference between the output angular velocity and the second target angular velocity; and a database that sequentially accumulates the first target angular velocity, the degree of comfort, and a target degree of comfort, wherein the first target angular velocity determining unit adjusts the first moment of inertia in such a way as to reduce a difference between the target degree of comfort and the degree of comfort, using the first target angular velocity, the degree of comfort, and the target degree of comfort that are accumulated in the database. <EOS>