An air tool driven by an air motor, the air tool comprising: a tool housing having an air motor accommodating part accommodating the air motor and a tubular air supply/exhaust pipe accommodating part extending from the air motor accommodating part to a rear opening end, the air motor accommodating part having a compressed air inlet for supplying compressed air to the air motor and a compressed air outlet for discharging compressed air from the air motor, the compressed air inlet and the compressed air outlet both being open in the air supply/exhaust pipe accommodating part; an air supply pipe disposed in the air supply/exhaust pipe accommodating part of the tool housing, the air supply pipe having an air supply inlet located near the rear opening end to receive compressed air from a compressed air supply source, an air supply outlet communicated with the compressed air inlet, and an air supply flow path extending from the air supply inlet to the air supply outlet; and an exhaust pipe disposed in the air supply/exhaust pipe accommodating part of the tool housing, the exhaust pipe having an exhaust inlet communicated with the compressed air outlet, an exhaust outlet located near the rear opening end to discharge compressed air to an outside of the air supply/exhaust pipe accommodating part, and an exhaust flow path extending from the exhaust inlet to the exhaust outlet; wherein the exhaust pipe is a discrete member formed separately from the air supply/exhaust pipe accommodating part; wherein the air supply/exhaust pipe accommodating part has a top wall, a bottom wall, and sidewalls on opposite sides of the exhaust pipe and connecting the top wall and the bottom wall, characterized in that the exhaust pipe is disposed so that the exhaust pipe engages the sidewalls and a clearance is formed between the exhaust pipe and the top and bottom walls (32, 34), and in that at least one of the sidewalls has a recess so that a gap is formed between the exhaust pipe and the at least one of the sidewalls. a tool housing having an air motor accommodating part accommodating the air motor and a tubular air supply/exhaust pipe accommodating part extending from the air motor accommodating part to a rear opening end, the air motor accommodating part having a compressed air inlet for supplying compressed air to the air motor and a compressed air outlet for discharging compressed air from the air motor, the compressed air inlet and the compressed air outlet both being open in the air supply/exhaust pipe accommodating part; an air supply pipe disposed in the air supply/exhaust pipe accommodating part of the tool housing, the air supply pipe having an air supply inlet located near the rear opening end to receive compressed air from a compressed air supply source, an air supply outlet communicated with the compressed air inlet, and an air supply flow path extending from the air supply inlet to the air supply outlet; and an exhaust pipe disposed in the air supply/exhaust pipe accommodating part of the tool housing, the exhaust pipe having an exhaust inlet communicated with the compressed air outlet, an exhaust outlet located near the rear opening end to discharge compressed air to an outside of the air supply/exhaust pipe accommodating part, and an exhaust flow path extending from the exhaust inlet to the exhaust outlet; wherein the exhaust pipe is a discrete member formed separately from the air supply/exhaust pipe accommodating part; wherein the air supply/exhaust pipe accommodating part has a top wall, a bottom wall, and sidewalls on opposite sides of the exhaust pipe and connecting the top wall and the bottom wall, characterized in that the exhaust pipe is disposed so that the exhaust pipe engages the sidewalls and a clearance is formed between the exhaust pipe and the top and bottom walls (32, 34), and in that at least one of the sidewalls has a recess so that a gap is formed between the exhaust pipe and the at least one of the sidewalls.