A press machine including a crank mechanism and a motor control device for the press machine are provided which are capable of, even when small foreign bodies generating disturbances having smaller amplitudes than that of the steady disturbance caused due to change in the moment of inertia of the crank mechanism are caught in, reliably detecting those foreign bodies without arranging any sensor or the like dedicated for detecting the intrusion of foreign bodies, as well as realizing reduction in the price and the size of the press machine and increasing reliability thereof. The motor control device includes a disturbance observer unit (2) for calculating an estimated disturbance value with respect to a motor (1) based on a torque command and a motor velocity, and an intrusion detection section (3, 4, 5) for detecting, based on the estimated disturbance value, a state of a foreign body being caught between a press shaft (12) and a cushion shaft (15).