To provide a robot-laser sensor system provided with a function of automatically approaching a work starting location by searching a work line location.

A robot mounted with a laser sensor and a work tool at the finger part approaches a work starting location Q 1 by various kinds of serach operation route patterns (a) to (d). The pattern (a) is determined so as to evade an obstacle F and an obstacle shape part G. The locus can be fixed by designating the coordinate axis of a coordinate Σw, for instance. The patterns (b), (c) can be realized by performing a teaching of data for successively fixing the locus for a robot. As for the pattern (d), initial vector <V1>, a rotation angle θ and a normed growth factor γ are set by parameters, vector <Vi+1> is fixed from vector <Vi> which is calculated the previous time by an illustrated relation (rotation of θ and normed γ times) at the time of the calculation of incremental moving amount Δ of the (i+1)th (i=0, 1, 2) and <Vi+1>-<Vi> may be fixed as the (i+1)th incremental moving amount Δ.