Electrically heated catalyst device

An electrically heated catalyst device configured to purify exhaust gas of an internal combustion engine mounted on a vehicle, the device comprising:

• a catalyst support that is arranged inside an exhaust pipe of the internal combustion engine, and is made of an electroconductive material;
• a low-potential-side electrode that is fixed to an outer circumferential surface of the catalyst support, and is configured to be connected to a low-potential-side terminal of a vehicle on-board power source when the electrically heated catalyst device is assembled with the vehicle;
• and
• a high-potential-side electrode that is fixed to the outer circumferential surface of the catalyst support, and is configured to be connected to a high-potential-side terminal of the vehicle on-board power source when the electrically heated catalyst device is assembled with the internal combustion engine, wherein
• in a case in which a current value between two electrodes, which are the low-potential-side electrode and the high-potential-side electrode, is gradually increased from 0, the current value between the two electrodes is referred to as an electrode fusing current value when, in each of the low-potential-side electrode and the high-potential-side electrode, a temperature of any section of the electrode first reaches a melting point of a material of the electrode, and
• the low-potential-side electrode is configured to have a lower electrode fusing current value than the high-potential-side electrode.