Wearable electronic apparatus (10) comprising a rigid structure (11) with the at least partial function of a bracelet, able to be associated with the wrist and/or forearm of the user, and a display unit (13) for operating data mounted on the rigid structure (11), the rigid structure (11) comprising an inner surface (16) shaped and selectively adaptable to the terminal part of the radial flank of the user's forearm, so as to allow, on each occasion, an adaptation in size of the rigid structure (11) to the radial flank of the forearm, in order to guarantee a stable and univocal positioning of the rigid structure (11) substantially with any size whatsoever of the radial flank of the forearm. The display unit (13) is mounted outside the rigid structure (11), in substantial correspondence with the shaped inner surface (16), so as to face towards the user when the electronic apparatus (10) is worn in the natural position of coupling of the rigid structure (11) and the radial flank of the forearm.