A method for producing metal oxide particles, the method comprising: combining, in a reaction tube, a preheated metal chloride-containing gas with a preheated first gas which does not contain the metal chloride at a first junction to obtain a first combined gas; and combining the first combined gas with a preheated second gas which does not contain the metal chloride, at a second junction which is further downstream of the first junction, to obtain a second combined gas, wherein at least one of the metal chloride-containing gas and the first gas contains oxygen; the preheated metal chloride-containing gas is further heated in a region between the first junction and the second junction (referred to as first reaction zone) by combining the first gas with the metal chloride-containing gas at the first junction while setting the preheat temperature of the first gas at a temperature equal to or higher than the preheat temperature of the metal chloride-containing gas, and the first combined gas is further heated in a region downstream of the second junction by combining the second gas with the first combined gas at the second junction while setting the preheat temperature of the second gas at a temperature equal to or higher than the temperature of the first combined gas; the metal chloride is titanium tetrachloride, and the metal oxide particles are titanium oxide particles; the titanium oxide particles are decahedral titanium oxide particles; the preheat temperature of the metal chloride-containing gas is equal to or higher than 400°C and equal to or lower than 800°C; the first gas contains oxygen gas; the second gas contains oxygen gas; the time for which the first combined gas remains in the first reaction zone is adjusted to 30 to 400 milliseconds; and the Reynolds number of the second combined gas is adjusted to 10 to 10,000. combining, in a reaction tube, a preheated metal chloride-containing gas with a preheated first gas which does not contain the metal chloride at a first junction to obtain a first combined gas; and combining the first combined gas with a preheated second gas which does not contain the metal chloride, at a second junction which is further downstream of the first junction, to obtain a second combined gas, wherein at least one of the metal chloride-containing gas and the first gas contains oxygen; the preheated metal chloride-containing gas is further heated in a region between the first junction and the second junction (referred to as first reaction zone) by combining the first gas with the metal chloride-containing gas at the first junction while setting the preheat temperature of the first gas at a temperature equal to or higher than the preheat temperature of the metal chloride-containing gas, and the first combined gas is further heated in a region downstream of the second junction by combining the second gas with the first combined gas at the second junction while setting the preheat temperature of the second gas at a temperature equal to or higher than the temperature of the first combined gas; the metal chloride is titanium tetrachloride, and the metal oxide particles are titanium oxide particles; the titanium oxide particles are decahedral titanium oxide particles; the preheat temperature of the metal chloride-containing gas is equal to or higher than 400°C and equal to or lower than 800°C; the first gas contains oxygen gas; the second gas contains oxygen gas; the time for which the first combined gas remains in the first reaction zone is adjusted to 30 to 400 milliseconds; and the Reynolds number of the second combined gas is adjusted to 10 to 10,000.