An industrial robot comprises a column 1 fixed to an installation base BS, a first axis J1, which is a linear movement axis, a second axis J2 and a third axis J3, which are rotational axes, and a fourth axis J4 in the form of a driving axis (rotational axis) of a working tool. A food grade lubricating oil is used for the linear guide (2), ball screw (5), bearing (6), speed reducers (9, 19) and gears (10, 20, 30) of these axes. Oil seals (15, 25, 35) for sealing the food grade lubricating oil are made from a material which is harmless to human bodies, for example, a fluorine resin material, in consideration of their wear.