An impact tool comprising: a casing that supports a tip tool; a moving member that is reciprocatably provided in the casing and generates impact force to be transmitted to the tip tool; an electric motor that is provided in the casing and has an output shaft; a motion converting mechanism that is provided in the casing, converts rotary motion of the output shaft to reciprocating motion, and transmits the reciprocating motion to the moving member; and a vibration reducing mechanism that is movably provided in the casing and reduces a vibration of the casing, wherein the vibration reducing mechanism includes: a supporting member that is provided to be swingable in a direction of a center line of reciprocation of the moving member and is fixed to a fixing position provided on the casing, said fixing position being used as a supporting point; and a weight that is attached to a location of the supporting member that is closer to a free end of the supporting member than the fixing position, wherein in a plane including the center line, a gravity center of the weight and the fixing position are disposed at mutually different locations in a radial direction of the center line, in the plane including the center line, the fixing position is disposed on a side of a gravity center of the impact tool relative to the center line, characterized in that the supporting member has a hole or a recessed part penetrating therethrough in a direction along an axis of the output shaft, and the output shaft is inserted in the hole or recessed part. a casing that supports a tip tool; a moving member that is reciprocatably provided in the casing and generates impact force to be transmitted to the tip tool; an electric motor that is provided in the casing and has an output shaft; a motion converting mechanism that is provided in the casing, converts rotary motion of the output shaft to reciprocating motion, and transmits the reciprocating motion to the moving member; and a vibration reducing mechanism that is movably provided in the casing and reduces a vibration of the casing, wherein the vibration reducing mechanism includes: a supporting member that is provided to be swingable in a direction of a center line of reciprocation of the moving member and is fixed to a fixing position provided on the casing, said fixing position being used as a supporting point; and a weight that is attached to a location of the supporting member that is closer to a free end of the supporting member than the fixing position, wherein in a plane including the center line, a gravity center of the weight and the fixing position are disposed at mutually different locations in a radial direction of the center line, in the plane including the center line, the fixing position is disposed on a side of a gravity center of the impact tool relative to the center line, characterized in that the supporting member has a hole or a recessed part penetrating therethrough in a direction along an axis of the output shaft, and the output shaft is inserted in the hole or recessed part. a supporting member that is provided to be swingable in a direction of a center line of reciprocation of the moving member and is fixed to a fixing position provided on the casing, said fixing position being used as a supporting point; and a weight that is attached to a location of the supporting member that is closer to a free end of the supporting member than the fixing position, wherein in a plane including the center line, a gravity center of the weight and the fixing position are disposed at mutually different locations in a radial direction of the center line, in the plane including the center line, the fixing position is disposed on a side of a gravity center of the impact tool relative to the center line, the supporting member has a hole or a recessed part penetrating therethrough in a direction along an axis of the output shaft, and the output shaft is inserted in the hole or recessed part.