To provide a means for economically exchanging the cash registration recording memory IC substrate of an electronic cash register coping with a fiscal seal.

To the bottom part 1b of the case body of this electronic cash register, an IC substrate 6 loaded with a cash registration recording memory is tightly sealed, housed in an IC substrate housing body 3 and fixed. The IC substrate 6 is housed in the box-shaped housing part 3a of the IC substrate housing body 3, an adhesive material or the like is filled and it is tightly sealed. The attaching part 3b of the IC substrate housing body 3 tightly sealing and housing the IC substrate is mounted on a boss 1c provided on the bottom part 1b of the case body, a screw 5 is passed through a through-hole opened at the attaching part 3b and it is screwed to the boss 1c. A covering body 4 is put on and fixed to the head part of the screw 5 and it is prevented from being directly detached from the outside. When the IC substrate 6 becomes defective due to a fault or the like, by destroying the fixing part of the covering body 4, the IC substrate housing body 3 is detached from the bottom part 1b of the case body and exchanged.