The invention relates to a blocking mechanism for a skin incision device and to a method of controlling of a skin incision device by a blocking mechanism. The blocking mechanism comprises a blocking means and a trigger means, which by, respectively, a fixing means and a locating means are mounted in a housing of the cooperating incision device, and which are provided with an engaging means configured to cooperate mutually with each other so that an inadvertent firing of the blocking mechanism and an inadvertent actuation of the incision device prior to use of the device as well as a re-use of the device is not possible, and an indication of a state of use of the device by the blocking means and the trigger means is unambiguous.