A method of producing a lower olefin and BTX from stock oils selected from at least two kinds of oils is provided. The method includes a first catalytic cracking step of bringing one stock oil A into contact with a catalytic cracking catalyst; a second catalytic cracking step of bringing one stock oil B, having an aromatic component content smaller than that of the stock oil A, into contact with the catalytic cracking catalyst; and a separation and collection step of collecting the lower olefins and BTX from a product generated in the first and second catalytic cracking steps. A contact time A during which the stock oil A is in contact with the catalytic cracking catalyst in the first catalytic cracking step is longer than a contact time B during which the stock oil B is in contact with the catalytic cracking catalyst in the second catalytic cracking step.