An impact rotation tool comprising: a motor serves as a rotation drive source; an impact mechanism including an output shaft, which is rotatable by the motor, and an anvil, which is rotatable integrally with the output shaft, wherein the impact mechanism is configured to apply a striking impact to the anvil when the motor outputs rotation; a housing that covers the motor and the impact mechanism; a motor seat fastened to the motor to hold the motor in the housing; and a vibration reducer arranged between the housing and the motor seat to reduce striking vibration transmitted to the motor, characterized in that: the motor seat includes an annular body and two engagement portions, wherein the two engagement portions extend radially outward from two radially opposite sides of the body; the vibration reducer includes two motor vibration rubber guards, wherein each of the motor vibration rubber guards covers a corresponding one of the engagement portions from a radially outer side; each of the engagement portions includes contact surfaces which contact the housing in a rotation direction of the motor; and each of the motor vibration rubber guards includes slits that expose the contact surfaces of the corresponding engagement portion in the rotation direction of the motor. a motor serves as a rotation drive source; an impact mechanism including an output shaft, which is rotatable by the motor, and an anvil, which is rotatable integrally with the output shaft, wherein the impact mechanism is configured to apply a striking impact to the anvil when the motor outputs rotation; a housing that covers the motor and the impact mechanism; a motor seat fastened to the motor to hold the motor in the housing; and a vibration reducer arranged between the housing and the motor seat to reduce striking vibration transmitted to the motor, characterized in that: the motor seat includes an annular body and two engagement portions, wherein the two engagement portions extend radially outward from two radially opposite sides of the body; the vibration reducer includes two motor vibration rubber guards, wherein each of the motor vibration rubber guards covers a corresponding one of the engagement portions from a radially outer side; each of the engagement portions includes contact surfaces which contact the housing in a rotation direction of the motor; and each of the motor vibration rubber guards includes slits that expose the contact surfaces of the corresponding engagement portion in the rotation direction of the motor. the motor seat includes an annular body and two engagement portions, wherein the two engagement portions extend radially outward from two radially opposite sides of the body; the vibration reducer includes two motor vibration rubber guards, wherein each of the motor vibration rubber guards covers a corresponding one of the engagement portions from a radially outer side; each of the engagement portions includes contact surfaces which contact the housing in a rotation direction of the motor; and each of the motor vibration rubber guards includes slits that expose the contact surfaces of the corresponding engagement portion in the rotation direction of the motor.