A master-slave device grips an object and performs a task while being in contact with a to-be-treated object. A force detection unit measures force information given to a slave mechanism. A force correction determination unit determines a force correction part serving as information from correction start to end times of force information transmitted to a master mechanism and, as a correcting method to perform correction, a first method determining a gain such that a reduction in absolute value of force information at the force correction part is maintained for a predetermined period of time or a second method determining a gain such that a reduction and an increase in the absolute value are repeated within a range that is not more than a value by reducing the absolute value. A force correction unit corrects information of a type of a force based on the force correction part and the gain.