Abstract: A processing time prediction method includes the following steps. A plurality of sampling points are set, defined by segmenting an operation time period into respective sampling time intervals. A posture assumed by a first robot and a posture assumed by a second robot for each of the sampling points are calculated, and a posture calculation time is measured. The posture assumed by the first robot and the posture assumed by the second robot for each of the sampling points are calculated, the presence or absence of interference is detected, and a posture calculation and interference detection time is measured. An interference detection time at the plurality of sampling points is computed, from a difference between the posture calculation and interference detection time and the posture calculation time. A unit processing time is computed by dividing the interference detection time by a number of the set sampling points.