To provide a jig saw wherein a structure of a surface plate itself is simplified, a manufacturing cost is maintained inexpensive, and further a light weight and miniaturization are attained.

A jig saw is equipped with a housing 1 which contains a motor 2, a converting mechanism T for converting the rotary motion to a linearly reciprocating motion, and a spindle 11 reciprocating up and down by the converting mechanism. A surface plate fitting part is integrally formed to a lower part of the housing 1, and the surface plate 16 is fixed thereto. In the housing 1 a switch 19 is provided downward therein, a grip 17 is slidably provided in an upper part of the housing 1, and the grip 17 is connected to the switch 19 via a swing arm 18 so that the switch 19 is allowed to turn on/off by the operation of the grip 17.