Fixing system adapted to be fixed in a removable manner on a penetrable surface, the fixing system comprising a housing base part and a pair of pin blocks mounted in the housing. Each pin block comprises a rigid body portion and a plurality of pins inclined obliquely in relation to said body portion. The pins of one pin block are oriented in a direction opposed to the direction of the pins of the other pin block, whereby an actuator mechanism moves the pin blocks apart or together, from a disengaged position to an engaged and stable position.