Surgical guidance device for patient-specific guidance of at least one tool used during a surgical intervention, comprising at least the following features: a) at least one carrier system which is arranged for fixation on a bone structure of a patient, b) at least one guiding system connectable to the carrier system, the at least one guiding system comprising at least one base module and at least one guiding part for precisely defined guidance of at least one tool used during the surgical intervention, c) at least one connecting means for establishing a mechanical connection between the at least one guiding part and the at least one base module, wherein the connecting means comprises at least a non-fixed operating state and a fixed operating state, wherein in the non-fixed operating state the at least one guiding part can be adjusted relative to the base module in a patient-specific adjustment and in the fixed operating state the at least one guiding part is mechanically fixated relative to the at least one base module in the patient-specific adjustment, d) at least one mechanical interface for connecting the carrier system to the guiding system, comprising first interface means (11, 12, 16) of the carrier system and second interface means (21, 22, 26) of the guiding system, wherein the first interface means (11, 12, 16) can be connected via form fit with the second interface means (21, 22, 26), at least in part, thereby ensuring a defined adjustment of the guiding system relative to the carrier system by means of form fit, characterized in that the at least one connecting means comprises at least a modifiable material with figurine and/or plastic properties, which is in the non-fixed operating state manually deformable and allows a patient-specific adjustment of the at least one guiding part relative to the at least one base module, wherein the deformable material can be rapidly hardened and/or cured, for transforming the connecting means into the fixed operating state. a) at least one carrier system which is arranged for fixation on a bone structure of a patient, b) at least one guiding system connectable to the carrier system, the at least one guiding system comprising at least one base module and at least one guiding part for precisely defined guidance of at least one tool used during the surgical intervention, c) at least one connecting means for establishing a mechanical connection between the at least one guiding part and the at least one base module, wherein the connecting means comprises at least a non-fixed operating state and a fixed operating state, wherein in the non-fixed operating state the at least one guiding part can be adjusted relative to the base module in a patient-specific adjustment and in the fixed operating state the at least one guiding part is mechanically fixated relative to the at least one base module in the patient-specific adjustment, d) at least one mechanical interface for connecting the carrier system to the guiding system, comprising first interface means (11, 12, 16) of the carrier system and second interface means (21, 22, 26) of the guiding system, wherein the first interface means (11, 12, 16) can be connected via form fit with the second interface means (21, 22, 26), at least in part, thereby ensuring a defined adjustment of the guiding system relative to the carrier system by means of form fit,