Signal transmitting device for a steering

An upper case (32) is rotatably provided in a body portion (31) to be fixed to an end face on the column side, and a spiral cable (29) is spirally accommodated in an annular space between the body portion (31) and the upper case (32). A cancel cam (40) for pressing a cancel portion (42) of a turn signal lever (36) with return rotation of a steering is protruded in a predetermined position on an outer peripheral surface of the upper case (32). A flange portion (41) is integrally formed on the cancel cam (40) over the outer peripheral surface of the upper case (32). A side wall (31B) to circulate and surround the flange portion (41) of the upper case (32) is erected on an upper surface of the body portion (31).