A combined working machine includes a base frame having a sloped surface, a first headstock installed on the sloped surface, a first main spindle rotatably provided on the first headstock, a second headstock installed on the sloped surface oppositely to the first headstock, a second main spindle provided on the second headstock, a tool head installed on the sloped surface on one side of the first headstock, a tool head provided in the tool head and having a tool attachment base to which a cutting tool is attached, a grinding head installed on the sloped surface on another side of the first headstock, and a grinding head body provided in the grinding head and supports a rotatable rotary shaft. A grinding wheel for grinding is exchangeably attached to the rotary shaft of the grinding head. According to the combined working machine, cutting and grinding can be carried out concurrently.