A particulate matter detecting apparatus that measures an amount of particulate matter in a gas, comprising: a solid electrolyte that has oxygen ion conductivity that transmits oxygen ions; a sensor element portion that measures the amount of particulate matter in the gas and includes a pair of first electrodes (8, 10) set as positive electrodes and a second electrode set as a negative electrode, wherein the pair of first electrodes (8, 10) is arranged to contact one surface of the solid electrolyte and the second electrode is arranged to contact the other surface of the solid electrolyte on a side opposite the one surface that the first electrodes (8, 10) contact, thereby sandwiching the solid electrolyte between the second electrode and the first electrodes (8, 10); the particulate matter detecting apparatus further comprising a detecting portion that detects whether more particulate matter than a reference amount has accumulated on the first electrodes (8, 10); a heating portion that heats the first electrodes (8, 10) and the second electrode; a temperature controlling portion that controls a temperature of the sensor element portion to become equal to or higher than a reference temperature when it is detected that more particulate matter than the reference amount has accumulated; and a voltage controlling portion that applies a reference voltage between the first electrodes (8, 10) and the second electrode; characterized in that a predetermined voltage is applied between the pair of first electrodes (8, 10) so as to detect the amount of particulate matter accumulated on the pair of first electrodes (8, 10) by detecting a current when the predetermined voltage is applied and calculating a resistance according to the detected current, and, when it is detected that more particulate matter than the reference amount has accumulated on the first electrodes (8, 10), the first electrodes (8, 10) are heated by the heating portion and the voltage controlling portion applies the reference voltage between the first electrodes (8, 10) and the second electrode so that oxygen ions are produced at the second electrode and the produced oxygen ions are pumped through the solid electrolyte and reach the first electrodes (8, 10) to react with the particulate matter adhered to the first electrodes, thereby removing the particulate matter adhered to the first electrodes. a solid electrolyte that has oxygen ion conductivity that transmits oxygen ions; a sensor element portion that measures the amount of particulate matter in the gas and includes a pair of first electrodes (8, 10) set as positive electrodes and a second electrode set as a negative electrode, wherein the pair of first electrodes (8, 10) is arranged to contact one surface of the solid electrolyte and the second electrode is arranged to contact the other surface of the solid electrolyte on a side opposite the one surface that the first electrodes (8, 10) contact, thereby sandwiching the solid electrolyte between the second electrode and the first electrodes (8, 10); a detecting portion that detects whether more particulate matter than a reference amount has accumulated on the first electrodes (8, 10); a heating portion that heats the first electrodes (8, 10) and the second electrode; a temperature controlling portion that controls a temperature of the sensor element portion to become equal to or higher than a reference temperature when it is detected that more particulate matter than the reference amount has accumulated; and a voltage controlling portion that applies a reference voltage between the first electrodes (8, 10) and the second electrode; characterized in that a predetermined voltage is applied between the pair of first electrodes (8, 10) so as to detect the amount of particulate matter accumulated on the pair of first electrodes (8, 10) by detecting a current when the predetermined voltage is applied and calculating a resistance according to the detected current, and, when it is detected that more particulate matter than the reference amount has accumulated on the first electrodes (8, 10), the first electrodes (8, 10) are heated by the heating portion and the voltage controlling portion applies the reference voltage between the first electrodes (8, 10) and the second electrode so that oxygen ions are produced at the second electrode and the produced oxygen ions are pumped through the solid electrolyte and reach the first electrodes (8, 10) to react with the particulate matter adhered to the first electrodes, thereby removing the particulate matter adhered to the first electrodes.