A power supply system for supplying electric power to first and second load devices, comprising: a first electric power line pair (MPL, MNL) electrically connected to said first load device (MG1, MG2); a plurality of rechargeable power storage units (10, 20, 20_1 to 20_N); a plurality of voltage conversion units (18, 28, 28_1 to 28_N) arranged corresponding to said plurality of power storage units (10, 20, 20_1 to 20_N) respectively, said plurality of voltage conversion units (18, 28, 28_1 to 28_N) being connected in parallel to said first electric power line pair (MPL, MNL) and each being configured to perform a voltage conversion operation between said first electric power line pair (MPL, MNL) and corresponding said power storage unit; a plurality of disconnection units (SMR1, SMR2, SMR2_1 to SMR2_N) arranged corresponding to said plurality of power storage units (10, 20, 20_1 to 20_N) respectively, each for electrically disconnecting corresponding said power storage unit and corresponding said voltage conversion unit from each other; a second electric power line pair (LPL, LNL) having one end electrically connected between a first voltage conversion unit representing one of said plurality of voltage conversion units (18, 28, 28_1 to 28_N) and corresponding said disconnection unit and another end electrically connected to said second load device (70, 80, 82); and a control unit for controlling said plurality of voltage conversion units, when one disconnection unit among said plurality of disconnection units (SMR1, SMR2, SMR2-1 to SMR_N) electrically disconnects corresponding said power storage unit and corresponding said voltage conversion unit from each other, such that electric power supply to said first load device (MG1, MG2) and electric power supply to said second load device (70, 80, 82) are continued through said first electric power line pair (MPL, MNL) and through said second electric power line pair (LPL, LNL) respectively by using electric power from remaining said power storage unit. a first electric power line pair (MPL, MNL) electrically connected to said first load device (MG1, MG2); a plurality of rechargeable power storage units (10, 20, 20_1 to 20_N); a plurality of voltage conversion units (18, 28, 28_1 to 28_N) arranged corresponding to said plurality of power storage units (10, 20, 20_1 to 20_N) respectively, said plurality of voltage conversion units (18, 28, 28_1 to 28_N) being connected in parallel to said first electric power line pair (MPL, MNL) and each being configured to perform a voltage conversion operation between said first electric power line pair (MPL, MNL) and corresponding said power storage unit; a plurality of disconnection units (SMR1, SMR2, SMR2_1 to SMR2_N) arranged corresponding to said plurality of power storage units (10, 20, 20_1 to 20_N) respectively, each for electrically disconnecting corresponding said power storage unit and corresponding said voltage conversion unit from each other; a second electric power line pair (LPL, LNL) having one end electrically connected between a first voltage conversion unit representing one of said plurality of voltage conversion units (18, 28, 28_1 to 28_N) and corresponding said disconnection unit and another end electrically connected to said second load device (70, 80, 82); and a control unit for controlling said plurality of voltage conversion units, when one disconnection unit among said plurality of disconnection units (SMR1, SMR2, SMR2-1 to SMR_N) electrically disconnects corresponding said power storage unit and corresponding said voltage conversion unit from each other, such that electric power supply to said first load device (MG1, MG2) and electric power supply to said second load device (70, 80, 82) are continued through said first electric power line pair (MPL, MNL) and through said second electric power line pair (LPL, LNL) respectively by using electric power from remaining said power storage unit.