Abstract: The present invention is an electric capacitance strain gauge provided with a pair of installing frames connected to each other, electrical insulating members with a stepped shape fixed onto the said pair of installing frames by insertion and two pairs of electrode plates with a stepped shape fixed onto the said electrical insulating members by insertion. As the electrical insulating members and the installing frames are positioned at a stepped part of the stepped shape when the electrical insulating members are fixed on the installing frames by insertion, and positioning of the electrode plates and the electrical insulating members is carried out at a stepped part of the electrode plates when the electrode plates are installed on the electrical insulating members by insertion, the relative positions of each member can be accurately determined.