The invention is a monitoring apparatus for monitoring a condition of an end-effector of a robot having a vacuum absorption pad to hold an article. The pad is elastically supported by the end-effector. The apparatus includes a pad receiving part having a front surface and a through hole, the pad receiving part being movable in a direction perpendicular to the front surface; an elastically supporting unit for elastically supporting the pad receiving part in a direction perpendicular to the front surface; a movement detection unit for detecting a movement of the pad receiving part; a vacuum sensor connected to the through hole; and a judging unit for judging conditions of an elastic support of the pad and a vacuum absorption of the pad based on detection results of the movement detection unit and the vacuum sensor.