A particulate matter detection device includes a sensor unit which has a detection unit provided with a pair of electrodes and a heater unit provided with a heater electrode and which is configured to output a signal corresponding to the amount of particulate matter, and a sensor control unit which detects the number of particles of the particulate matter. The sensor control unit has a capture control unit, a heating control unit to heat the detection unit to a first temperature at which a SOF is volatilizable and a second temperature at which soot is burnable, an output changing ratio calculation unit to calculate a ratio between a first output value at the first temperature and a second output value as the maximum output upon heating to the second temperature, and a particle number calculation unit to estimate the average particle diameter of the particulate matter from a value corrected based on the temperature of the sensor unit at the second output value to calculate the number of particles.