A slewing apparatus comprising: a base; a slewing body slewably supported by the base; a boom supported by a slewing base in a derricking and telescopic manner; a hook suspended by a rope from a tip portion of the boom; a slewing actuator that allows the slewing body to slew; and a control section that controls the slewing actuator, wherein the control section performs an acquisition process of acquiring a slewing start position and a slewing end position of the slewing body, and a pendulum length that is a length from the tip portion of the boom to a suspended load suspended from the hook; characterized in that the control section performs: a slewing angular velocity pattern determination process of determining a slewing angular velocity pattern by optimum control in a first interval and a second interval, the slewing angular velocity pattern indicating transition of an angular velocity of the tip potion of the boom when the slewing body slews from the slewing start position to the slewing end position, the first interval being an interval in which the angular velocity is accelerated from the slewing start position, and decelerated, and accelerated to be a slewing angular velocity ω, the second interval being an interval in which the angular velocity is decelerated from the slewing angular velocity ω, and accelerated, and decelerated to be stopped at the slewing end position; and an actuator control process of controlling the slewing actuator to allow the slewing body to slew from the slewing start position to the slewing end position such that the tip portion of the boom moves in a slewing direction at a velocity indicated by the slewing angular velocity pattern, wherein in the slewing angular velocity pattern determination process, the slewing angular velocity pattern is determined such that in the first interval and the second interval of a control time T that is shorter than a cycle determined by the pendulum length of the suspended load that is in a pendulum motion, a difference between a maximum angular velocity and a minimum angular velocity increases as the control time T decreases. a base; a slewing body slewably supported by the base; a boom supported by a slewing base in a derricking and telescopic manner; a hook suspended by a rope from a tip portion of the boom; a slewing actuator that allows the slewing body to slew; and a control section that controls the slewing actuator, wherein the control section performs an acquisition process of acquiring a slewing start position and a slewing end position of the slewing body, and a pendulum length that is a length from the tip portion of the boom to a suspended load suspended from the hook; characterized in that the control section performs: a slewing angular velocity pattern determination process of determining a slewing angular velocity pattern by optimum control in a first interval and a second interval, the slewing angular velocity pattern indicating transition of an angular velocity of the tip potion of the boom when the slewing body slews from the slewing start position to the slewing end position, the first interval being an interval in which the angular velocity is accelerated from the slewing start position, and decelerated, and accelerated to be a slewing angular velocity ω, the second interval being an interval in which the angular velocity is decelerated from the slewing angular velocity ω, and accelerated, and decelerated to be stopped at the slewing end position; and an actuator control process of controlling the slewing actuator to allow the slewing body to slew from the slewing start position to the slewing end position such that the tip portion of the boom moves in a slewing direction at a velocity indicated by the slewing angular velocity pattern, wherein in the slewing angular velocity pattern determination process, the slewing angular velocity pattern is determined such that in the first interval and the second interval of a control time T that is shorter than a cycle determined by the pendulum length of the suspended load that is in a pendulum motion, a difference between a maximum angular velocity and a minimum angular velocity increases as the control time T decreases. a slewing angular velocity pattern determination process of determining a slewing angular velocity pattern by optimum control in a first interval and a second interval, the slewing angular velocity pattern indicating transition of an angular velocity of the tip potion of the boom when the slewing body slews from the slewing start position to the slewing end position, the first interval being an interval in which the angular velocity is accelerated from the slewing start position, and decelerated, and accelerated to be a slewing angular velocity ω, the second interval being an interval in which the angular velocity is decelerated from the slewing angular velocity ω, and accelerated, and decelerated to be stopped at the slewing end position; and an actuator control process of controlling the slewing actuator to allow the slewing body to slew from the slewing start position to the slewing end position such that the tip portion of the boom moves in a slewing direction at a velocity indicated by the slewing angular velocity pattern, wherein in the slewing angular velocity pattern determination process, the slewing angular velocity pattern is determined such that in the first interval and the second interval of a control time T that is shorter than a cycle determined by the pendulum length of the suspended load that is in a pendulum motion, a difference between a maximum angular velocity and a minimum angular velocity increases as the control time T decreases.