PURPOSE:To select an optional one of processing interruption states of the past and to enable a user to resturn to the selected state by providing a selection means which stores those processing interruption states and selects one of plural storage means that hold their storage contents despite of an OFF state of a power supply. CONSTITUTION:Plural storage means 2 are provided to store the processing interruption states and to hold the storage contents despite an OFF state of a power supply. Then a selection means 3 selects one of those processing interruption states stored in the storage means 2. Therefore a user can return to the precedent processing state of his/her own when plural users share a single information processor. Meanwhile the user can return to his/her desired processing state when a single user performs plural processing operations in parallel with each other with use of a single information processor. Thus it is possible to select the optional one of plural processing interruption states stored in the storage means 2 by selecting one of these means. Then the user can return to the selected state.
