PURPOSE: To facilitate taking-out of current by disengaging the lock of a battery lid with its displacement associate with an intrusive motion of battery to a stepped part, and thereby making lock disengagement of the battery lid and the rising motion of the battery simultaneously

CONSTITUTION: In the same manner as removal of a battery lid 3, taking-out of a battery 20 is made by pressing a recess 15 provided at the flat part 3a of the battery lid 3. That is, pressing the recess 15 in the direction of arrow D actuates intrudive motion of battery lid 3 to a stepped part 16a provided for battery lid and an intrusive motion of the battery 20 to a stepped part 26a, and thereby the battery lid 3 and battery 20 are inclined. Inclination of the battery lid 3 disengages the lock of a detent piece 12 with a detent projection 14, so that the battery lid 3 can be set free relative to a cabinet 1 by sliding the battery lid 3 in the direction of arrow B.