To provide technique effective for improving smoothness of speed change operation and improving convenience for a power tool having a parallel shaft type speed change mechanism.

The speed change mechanism for the power tool having the speed change mechanism 117 and a distal end tool includes first and second rotational shafts 123, 125 disposed in parallel to each other, a first power transmission passage P1 having a first gear train and a first clutch 141, and a second power transmission passage having a second gear train and a second clutch 145. A power transmission state and a power cut-off state of the first and second clutches are switched corresponding to load applied to the distal end tool to switch between the first and second transmission passages with the first and second gear trains engaged. Moreover, the speed change mechanism has a switch-over setting value adjustment mechanism operated by a user for adjusting a switch-over setting value to regulate switch-over between the first and second power transmission passages.

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