A shift device of a transmission includes: a cylindrical or columnar shift cam that is formed, at an outer circumferential surface of the shift cam, with a cam groove for operating a shift fork; a drive plate that oscillates by rotation of a shift pedal shaft; a shift cam plate that is fixed to one end portion of the shift cam and rotates the shift cam according to the oscillation of the drive plate; a shift cam sensor that detects a rotation angle of the shift cam; and a transmission shaft that transmits the rotation of the shift cam to the shift cam sensor, as defined herein.