A 3D measuring device is provided. The device includes a measuring head with a light transmitter and a light receiver. A control and evaluation device is coupled to the light transmitter and light receiver and determines the distance to the object. An accessory interface allows an accessory device to be mechanically connected to the measuring head and can be electrically connected to the control and evaluation device. The accessory interface includes a receiving section and a contact section. The receiving and contact sections are arranged such that the accessory device can be inserted into the accessory interface in an insertion direction in order to electrically and mechanically couple the accessory device to the accessory interface. A support structure having an integral slot is coupled to the measuring head. The slot has the receiving section for the mechanical connection and the at least one contact section.