IN-TIRE ELECTRIC DEVICE

An in-tire electric device having a bracket and an electric circuit unit detachably held by the bracket includes: an engagement protrusion and an engagement hole provided on the electric circuit unit and the bracket to engage with each other to restrict, through a two-step operation where the electric circuit unit is moved in a first direction and then moved or rotated in a second direction intersecting the first direction, all movements and rotations except for a reverse of the second direction; a retainer mounted on the bracket from a direction intersecting the second direction and facing the electric circuit unit in the second direction to restrict the electric circuit unit from moving in the second direction; and retainer locking portions formed on the bracket and the retainer and engage with each other by elastic deformation of one of the retainer locking portions to lock the retainer to the bracket.