To improve safety by lowering stimulus intensity or stopping an electric stimulus before an objective person feels pain when the stimulus is imparted to this person.

An effector 1a of the electric stimulus device 1 having the effector for imparting the electric stimulus to the muscle is provided with an electrode section 1ad consisting of an electrode group used by coming into contact with a skin surface, a shape information acquiring section 1as for acquiring the information indicating the shape and shape change of the skin surface and a resistance value detecting means 1r for detecting the resistance values between each other respectively with respect to the electrode group and acquiring the resistance value thereof. The specific resistance values per unit length or area or volume meeting the materials of the bones, muscles, fats, skin, etc., are previously registered in a data base of the human structures relating to the objective persons. The resistance distributions within the human body or on the skin surface are calculated from the resistance values of the skin surfaces obtained by the resistance value detecting means 1r and the body data and registered specific resistance values of the objective person based on the data base, by which the insulation resistance values are determined.