Automatic hooking device with controlled releasing operation for blocks for ships, boats, vessels or equivalent means for transportation of both goods and passengers, comprising first hooking means for engaging members of said block, which are operated only by the ascending movement of said block, intended for fixing said lifting blocks on a supporting structure, wherein it comprises at least one hooking/unhooking device consisting of a system of movable levers (2, 3, 4) being reciprocally interconnected by means of pins (5, 6, 7) and being shaped to carry out a movement between at least two end position, one of which is a first position, in which said hooking/unhooking device is in an engagement condition of said engaging members and another of which is a second position, in which said hooking/unhooking device is in a release condition of said engaging members, wherein in said engagement condition of said engaging members the axes of said pins (5, 6, 7) are in a condition close to reciprocal alignment condition of said pins (5, 6, 7) according to a certain alignment/misalignment degree of said pins (5, 6, 7), and wherein said system of movable levers (2, 3, 4), which are reciprocally interconnected are made of: - a counteracting lever being hinged in correspondence with one of its first ends by a first pin and rotating freely about said first pin being in a fixed position with respect to said supporting structure of said lifting blocks; - a connecting rod having a first end fixed to said counteracting lever by a second pin, wherein said first end of said connecting rod rotates freely about said second pin being movable with respect to said supporting structure of said blocks, and wherein only a reciprocal constraint is present between the two respective ends of said connecting rod and said counteracting lever; - a hooking element having a first end fixed to said connecting rod by a third pin, wherein said first end of said hooking element rotates freely about said third pin being movable with respect to said supporting structure, being only present a reciprocal constraint between the two respective ends of said connecting rod and said hooking element having a fulcrum point and being free to rotate about said fulcrum being in a fixed position with respect to said supporting structure; wherein said hooking/unhooking device comprises a control device fixed to one of the elements of said system of movable levers (2, 3, 4) by a coupling, characterised in that, in said engagement condition of said engaging members said first pin is in between with respect to said second pin and third pin, and in said release condition of said engaging members said second pin is in between with respect to said first pin and third pin, and in that, a force can be applied to said control device alternatively constituting a retaining force of said engagement condition of said hooking/unhooking device or constituting a force starting the releasing movement of said hooking/unhooking device according to the alignment/misalignment degree which is present in said condition close to reciprocal alignment condition of said pins (5, 6, 7). - a counteracting lever being hinged in correspondence with one of its first ends by a first pin and rotating freely about said first pin being in a fixed position with respect to said supporting structure of said lifting blocks; - a connecting rod having a first end fixed to said counteracting lever by a second pin, wherein said first end of said connecting rod rotates freely about said second pin being movable with respect to said supporting structure of said blocks, and wherein only a reciprocal constraint is present between the two respective ends of said connecting rod and said counteracting lever; - a hooking element having a first end fixed to said connecting rod by a third pin, wherein said first end of said hooking element rotates freely about said third pin being movable with respect to said supporting structure, being only present a reciprocal constraint between the two respective ends of said connecting rod and said hooking element having a fulcrum point and being free to rotate about said fulcrum being in a fixed position with respect to said supporting structure;