Variable half-scale harmonica

The utility model discloses a harmonica capable of playing half scales, and relates to the technical field of harmonica. The harmonica comprises a harmonica body, a mouthpiece plate is fixed at the front ends of fret sound holes of the harmonica body, blowing ports corresponding to each pair of fret sound holes in a one-to-one manner are arranged on the mouthpiece plate, a variable part is rotatably connected between the front ends of each pair of fret sound holes and each blowing port, and an air guide hole is arranged on the variable part. The air blowing port is communicated with one of each pair of fret sound holes through the air guide hole, the variable part is of a disc body structure, teeth are arranged on the peripheral side face of the variable part, and the teeth of every two adjacent variable parts are meshed with each other. According to the utility model, the mouthpiece plate is installed at the front end of the sound hole, and the position of the semitone hole is adjusted by the air blowing por