An apparatus for verifying the presence, or the absence, of an
abrasive element in a
machine for finishing surfaces comprising a support body configured to removably engage the
abrasive element. The support body and the
abrasive element are, respectively, provided, at respective engagement surfaces with first and second engagement elements configured to move from an engagement configuration to a disengagement configuration, and vice versa. Furthermore, a displacement device is provided to move the support body in the space according to at least 1 degree of freedom. The apparatus, furthermore, provides at least a control
station equipped with a control device comprising a control element having a control surface provided with third engagement elements configured to engage with the first engagement elements of the support body, and a detection device configured to detect if an engagement between the control element and the support body has taken place.