Fixing device for a control and/or signalling component designed to be inserted through an opening produced in a wall and which comprises a tubular support designed to come into abutment against a first face of the wall, said device comprising: - a base having an axial opening in a main direction, designed to receive said body of the control and/or signalling component, said base being oriented between a zone, called front zone, and a zone, called rear zone, in a direction, called assembly direction, that is perpendicular to said main direction, and comprising a support, to which the tubular body is fixed, a plate that is fixed on said support and comprises means for fixing one or more detachable electrical contact or signalling blocks (4a, 4b), said fixing means comprising, for each contact or signalling block, a bay located in the rear zone and designed to engage with an attachment latch of the contact or signalling block and an attachment socket located in the front zone and designed to engage with a resilient attachment component of the contact or signalling block (4a, 4b), characterized in that: - the base comprises a first orifice defining a first front zone axis and a second orifice defining a second rear zone axis that is parallel to said first axis and is perpendicular to said assembly direction; - the device comprises a first fixing screw to be screwed into said first orifice in order to press against a second face of the wall and a second fixing screw to be screwed into said second orifice against said second face of the wall, and in that - the plate comprises a part perpendicular to said main direction, through which said axial opening is produced, and a curved part, through which each bay is produced for receiving an attachment latch of an electrical or signalling contact block, said curved part being formed in a plane perpendicular to the assembly direction and located between said first axis and said second axis. - a base having an axial opening in a main direction, designed to receive said body of the control and/or signalling component, said base being oriented between a zone, called front zone, and a zone, called rear zone, in a direction, called assembly direction, that is perpendicular to said main direction, and comprising a support, to which the tubular body is fixed, a plate that is fixed on said support and comprises means for fixing one or more detachable electrical contact or signalling blocks (4a, 4b), said fixing means comprising, for each contact or signalling block, a bay located in the rear zone and designed to engage with an attachment latch of the contact or signalling block and an attachment socket located in the front zone and designed to engage with a resilient attachment component of the contact or signalling block (4a, 4b), - the base comprises a first orifice defining a first front zone axis and a second orifice defining a second rear zone axis that is parallel to said first axis and is perpendicular to said assembly direction; - the device comprises a first fixing screw to be screwed into said first orifice in order to press against a second face of the wall and a second fixing screw to be screwed into said second orifice against said second face of the wall, and in that - the plate comprises a part perpendicular to said main direction, through which said axial opening is produced, and a curved part, through which each bay is produced for receiving an attachment latch of an electrical or signalling contact block, said curved part being formed in a plane perpendicular to the assembly direction and located between said first axis and said second axis.