PURPOSE: To prevent the leading tip of an upper case from lifting by a method wherein a lower case which is provided by a hinge provided at the base part of an upper case is equipped, and protuberances are provided on the outer surfaces on both sides at the leading end of the upper case, and at the same time, recessed parts which can be engaged with the protuberances are provided on the inner surfaces on both sides at the leading end of the lover case.

CONSTITUTION: A front surface plate part 40 and right and left side plate parts 41 are respective provided at the leading end 39 side and both sides of a flat plate part 38, and in addition, a protuberance 43 which is inserted in a hole 35 is provided on the inner surface of base parts 42 which are formed by extending the right and left side plate parts 41. Then, a lower case 30 is closed to be fitted on an upper case 27 around a hinge 29 as the rotational center. In this case, a recessed part 51 side which is provided on the lower case 30 is slightly pushed open by a protuberance 49, and then the recessed part 51 provided on the lower case 30 is engaged with the protuberance 49, and the upper case 27 and lower case 30 can be prevented from being opened during storage. A leading end 28 of the upper case 27 slightly protrudes into an arc shape along the longitudinal direction. As the result, the protuberance 49 provided on the upper case 27 is removed from from the recessed part 51, and then the upper case 27 is further opened, and at the same time, a cassette tape 21 is removed from a pocket 25.