Connection device for two furniture parts which have to be interconnected, with a first connection portion which is realized at least as a spreading system and which is intended for being provided in a recess in a first furniture part, with a second connection portion which is intended for extending outside of the recess for cooperating with a second furniture part in this manner, as well as an activation mechanism for activating the spreading system, wherein the spreading system comprises at least two mutually rotatable parts, a first part and a second part, respectively, wherein the mutual rotation of which, in function of the realized mutual angle position, effects a spreading effect.