A mobile apparatus or the like capable of moving or acting by avoiding contact with an object, such as a person, while reducing the possibility of inducing a change of the behavior of the object. It is determined whether or not there is a first spatial element Q.sub.1 that satisfies a contact condition that there is a possibility of contact with a reference spatial element Q.sub.0 on a discriminant plane. The reference spatial element Q.sub.0 and the first spatial element Q.sub.1 represent current images of a robot 1 and an object x, respectively. When it is determined that there is a first spatial element Q.sub.1 that satisfies the contact condition on the discriminant plane, a route that allows the reference spatial element Q.sub.0 to move by avoiding contact with a second spatial element Q.sub.2 is set as a new "first action plan element" on the discriminant plane.