The present invention relates to a portable terminal device, such as a cellular phone, which has a screen display section, such as an LCD module, in its upper part and a key manipulation section having an array of plural keys in its lower part. The portable terminal device has a removable battery and is highly protected from water especially in a battery area. There is provided a pair of inner housings, that are a backside inner housing and a front side inner housing, which form a battery compartment having an opening for battery insertion/removal. A key manipulation sheet is disposed on the front side inner housing, and the whole components are covered with a pair of outer housings.