The invention relates to an automatic device for simulating drilling of an anchor rod hole in a tunnel. A conical driven gear and a conical driving gear, which are engaged with each other, are disposed in a head housing. The conical driven gear is coaxially provided with a vertical shaft, a drill bit clamp, and a drill bit. The outer part of the head housing is provided with a displacement sensor on the same side of the drill bit. The bottom part of the conical driving gear is disposed on a transmission shaft, which is coaxially provided with at least a group of supporting shoes. The transmission shaft is coaxially disposed on a mini-sized rotating motor and a rotating shaft. The angle positioning gear of the bottom part of the rotating shaft is engaged with a gear of a mini-sized stepping motor. A computer control system is connected with the mini-sized stepping motor, the mini-sized rotating motor, and the displacement sensor. The drilling of the anchor rod hole in the specific position of the tunnel can be simulated accurately, and the operation is simple, and therefore the tunnel simulation testing result is accurate and reliable, the device provided by the invention can be widely used for the drilling of the anchor rod hole in the tunnel surrounding rock and other rock masses, and device can be cooperated with the test and the research of the tunnel surrounding rock and other rock masses.