A power tool, comprising: a housing; a saw blade for cutting a workpiece; a motor for driving the saw blade to rotate about a first axis; a circuit board for controlling the motor; a heat sink for cooling; and a base plate being formed with a flat surface for contacting with the workpiece during cutting, wherein the housing comprises: a first containing portion being formed with a first container for containing the motor, a second containing portion extended along a direction substantially parallel to the flat surface from one of the two ends of the first containing portion along a direction substantially perpendicular to the first axis, the second containing portion is formed with a second container which is communicated with the first container, the circuit board and the heat sink are disposed in the second container, characterized in that a distance from the second containing portion to the flat surface is greater than or equal to 8mm and less than or equal to 30mm in the direction substantially perpendicular to the flat surface; the heat sink comprises a base board extended along a direction substantially parallel to the flat surface and a plurality of first-type ribs having a first-type air outlet, wherein the first-type ribs are disposed on the base board, the first-type air outlet is aligned with one side of the first container that is far from the saw blade in a direction of the first axis, and the heat sink comprises a plurality of second-type ribs having a second-type air outlet, the second-type ribs are disposed on the base board, the second-type air outlet is aligned with a part of the first container for containing the motor in the direction of the first axis, the second-type ribs have an end close to the motor which is shorter than the first-type ribs in a direction substantially parallel to the flat surface and perpendicular to the first axis. a housing; a saw blade for cutting a workpiece; a motor for driving the saw blade to rotate about a first axis; a circuit board for controlling the motor; a heat sink for cooling; and a base plate being formed with a flat surface for contacting with the workpiece during cutting, wherein the housing comprises: a first containing portion being formed with a first container for containing the motor, a second containing portion extended along a direction substantially parallel to the flat surface from one of the two ends of the first containing portion along a direction substantially perpendicular to the first axis, the second containing portion is formed with a second container which is communicated with the first container, the circuit board and the heat sink are disposed in the second container, characterized in that a distance from the second containing portion to the flat surface is greater than or equal to 8mm and less than or equal to 30mm in the direction substantially perpendicular to the flat surface; the heat sink comprises a base board extended along a direction substantially parallel to the flat surface and a plurality of first-type ribs having a first-type air outlet, wherein the first-type ribs are disposed on the base board, the first-type air outlet is aligned with one side of the first container that is far from the saw blade in a direction of the first axis, and the heat sink comprises a plurality of second-type ribs having a second-type air outlet, the second-type ribs are disposed on the base board, the second-type air outlet is aligned with a part of the first container for containing the motor in the direction of the first axis, the second-type ribs have an end close to the motor which is shorter than the first-type ribs in a direction substantially parallel to the flat surface and perpendicular to the first axis. a first containing portion being formed with a first container for containing the motor, a second containing portion extended along a direction substantially parallel to the flat surface from one of the two ends of the first containing portion along a direction substantially perpendicular to the first axis, the second containing portion is formed with a second container which is communicated with the first container, the circuit board and the heat sink are disposed in the second container, characterized in that a distance from the second containing portion to the flat surface is greater than or equal to 8mm and less than or equal to 30mm in the direction substantially perpendicular to the flat surface; the heat sink comprises a base board extended along a direction substantially parallel to the flat surface and a plurality of first-type ribs having a first-type air outlet, wherein the first-type ribs are disposed on the base board, the first-type air outlet is aligned with one side of the first container that is far from the saw blade in a direction of the first axis, and the heat sink comprises a plurality of second-type ribs having a second-type air outlet, the second-type ribs are disposed on the base board, the second-type air outlet is aligned with a part of the first container for containing the motor in the direction of the first axis, the second-type ribs have an end close to the motor which is shorter than the first-type ribs in a direction substantially parallel to the flat surface and perpendicular to the first axis.