Disclosed herein is an automatic rotating interdental brush that automatically rotates a brush to efficiently clear away extraneous substances, plaque and the like trapped in between teeth by pushing and pulling a grip body while causing the brush to be in contact with the teeth. The automatic rotating interdental brush includes a body, a rotor that protrudes from and retracts into the body to rotate a brush, a brush coupled to the rotor, and a rotating unit for causing the rotor to protrude and retract while being rotated. The rotating unit includes a screw provided at a rear end of the rotor and having a spiral rotation guide groove longitudinally formed thereon, and a rotating guide hole formed in the body and having a shape corresponding to a cross-section of the screw so as to cause the screw disposed therein to be linearly moved while being rotated.
