An underactuated prosthetic hand comprising - a base body; - two pairs of prosthetic fingers comprising a first prosthetic finger and a second prosthetic finger; each of said prosthetic fingers being hinged to said base body; - a first control cable; - an actuator adapted to move said first control cable; - and for each one of said pair of prosthetic fingers ∘ a second control cables each having a first control end associated with said first prosthetic finger and a second control end associated with said second prosthetic finger; and ∘ a transmission block adapted to allow said first control cable to control said second control cable; - wherein said transmission block comprises - a guide integral with said base body and defining a sliding axis; - a movable element sliding along said guide; - a first pulley for the sliding of said first control cable hinged to said movable element and - a second pulley for the sliding of said second control cable hinged to said movable element so that said actuator, when it moves said first control cable, brings about a translational movement of said movable element along said guide, causing a displacement of said second control cable and therefore of said prosthetic fingers; and - elastic means suitable to work in opposition to a translational movement of said movable element so that said translational movement of said movable element is performed in opposition to said elastic means, allowing said elastic means to command the return to the initial position of said movable element when said actuator is deactivated, so as to facilitate the return to the initial position of said main fingers; characterised in that - said underactuated prosthetic hand comprises two of said at least one pair of prosthetic fingers; one said first control cable, two of said second control cable and two transmission blocks, each of which adapted to allow said first control cable to simultaneously control both said second control cables and thus both said pairs of prosthetic fingers; - said transmission block comprises two of said guide substantially parallel to each other; and wherein said movable element slides along said two guides; and - each of said prosthetic fingers comprises a return block adapted to work in opposition to a rotation of said prosthetic finger controlled by said second control cable. - a base body; - two pairs of prosthetic fingers comprising a first prosthetic finger and a second prosthetic finger; each of said prosthetic fingers being hinged to said base body; - a first control cable; - an actuator adapted to move said first control cable; - and for each one of said pair of prosthetic fingers ∘ a second control cables each having a first control end associated with said first prosthetic finger and a second control end associated with said second prosthetic finger; and ∘ a transmission block adapted to allow said first control cable to control said second control cable; ∘ a second control cables each having a first control end associated with said first prosthetic finger and a second control end associated with said second prosthetic finger; and ∘ a transmission block adapted to allow said first control cable to control said second control cable; - wherein said transmission block comprises - a guide integral with said base body and defining a sliding axis; - a movable element sliding along said guide; - a first pulley for the sliding of said first control cable hinged to said movable element and - a second pulley for the sliding of said second control cable hinged to said movable element so that said actuator, when it moves said first control cable, brings about a translational movement of said movable element along said guide, causing a displacement of said second control cable and therefore of said prosthetic fingers; and - elastic means suitable to work in opposition to a translational movement of said movable element so that said translational movement of said movable element is performed in opposition to said elastic means, allowing said elastic means to command the return to the initial position of said movable element when said actuator is deactivated, so as to facilitate the return to the initial position of said main fingers; characterised in that - said underactuated prosthetic hand comprises two of said at least one pair of prosthetic fingers; one said first control cable, two of said second control cable and two transmission blocks, each of which adapted to allow said first control cable to simultaneously control both said second control cables and thus both said pairs of prosthetic fingers; - said transmission block comprises two of said guide substantially parallel to each other; and wherein said movable element slides along said two guides; and - each of said prosthetic fingers comprises a return block adapted to work in opposition to a rotation of said prosthetic finger controlled by said second control cable.