To safely and easily perform attachment/detachment of a housing and a battery pack and to further attain stable and certain fixing.

The battery type power tool includes: the housing for storing a motor; and the battery pack for performing feeding of drive electric power to the motor by being detachably installed on the housing. Attachment/detachment of the battery pack to/from the housing is performed by slidingly moving the battery pack in an approximately parallel direction relative to an installment reference surface formed on the housing. The housing includes a slide rail 21 installed on the installment reference surface and having a claw engagement part 22 on a side surface, whereas, the battery pack includes an engagement claw 32 engageable/disengageable with/from the claw engagement part 22. Further, the housing includes an elastic member 27 for pressing the battery pack, and in the battery pack, a projection part 37 is provided at a position to be pressed by the elastic member 27.