A turn-on operation control apparatus of a switch unit included in a parallel multi battery pack, which controls a turn-on operation of switch units (S1-Sn) included in first to n th battery packs (P1-Pn) connected in parallel through a parallel link node, the turn-on operation control apparatus comprising: first to n th switch units (S1-Sn) respectively installed on power lines (C1-Cn) of the first to n th battery packs (P1-Pn); first to n th current sensors (I1-1n) connected to the switch units (S1-Sn) respectively installed on the power lines (C1-Cn) of the first to n th battery packs to measure currents flowing through the corresponding switch units (S1-Sn); first to n th voltage sensors (V1-Vn) respectively coupled to the first to n th switch units (S1-Sn) to measure both-end voltages of the corresponding switch units; and a control unit operatively coupled to the first to n th switch units (S1-Sn), the first to n th current sensors (I1-In) and the first to n th voltage sensors (V1-Vn), wherein the control unit is configured to: connect the first to n th battery packs (P1-Pn) in parallel by turning on the first to n th switch units (S1-Sn) according to a preset turn-on sequence before charging or discharging of the parallel multi battery pack is initiated, receive a switch voltage value from a voltage sensor coupled to a k th sequence switch unit, where k is a turn-on sequence index, which is a natural number of 2 to n, before turning on the k th sequence switch unit, then turn on the k th sequence switch unit, subsequently receive a switch current value from a current sensor connected to the k th sequence switch unit, and count a watt energy value consumed in the k th sequence switch unit from the switch voltage value and the switch current value, and determine the turn-on sequence of the first to n th switch units (S1-Sn) in descending order from a switch unit having a greatest watt energy count value by referring to watt energy count values respectively corresponding to the first to n th switch units before charging or discharging of the parallel multi battery pack is initiated. first to n th switch units (S1-Sn) respectively installed on power lines (C1-Cn) of the first to n th battery packs (P1-Pn); first to n th current sensors (I1-1n) connected to the switch units (S1-Sn) respectively installed on the power lines (C1-Cn) of the first to n th battery packs to measure currents flowing through the corresponding switch units (S1-Sn); first to n th voltage sensors (V1-Vn) respectively coupled to the first to n th switch units (S1-Sn) to measure both-end voltages of the corresponding switch units; and a control unit operatively coupled to the first to n th switch units (S1-Sn), the first to n th current sensors (I1-In) and the first to n th voltage sensors (V1-Vn), wherein the control unit is configured to: connect the first to n th battery packs (P1-Pn) in parallel by turning on the first to n th switch units (S1-Sn) according to a preset turn-on sequence before charging or discharging of the parallel multi battery pack is initiated, receive a switch voltage value from a voltage sensor coupled to a k th sequence switch unit, where k is a turn-on sequence index, which is a natural number of 2 to n, before turning on the k th sequence switch unit, then turn on the k th sequence switch unit, subsequently receive a switch current value from a current sensor connected to the k th sequence switch unit, and count a watt energy value consumed in the k th sequence switch unit from the switch voltage value and the switch current value, and determine the turn-on sequence of the first to n th switch units (S1-Sn) in descending order from a switch unit having a greatest watt energy count value by referring to watt energy count values respectively corresponding to the first to n th switch units before charging or discharging of the parallel multi battery pack is initiated. connect the first to n th battery packs (P1-Pn) in parallel by turning on the first to n th switch units (S1-Sn) according to a preset turn-on sequence before charging or discharging of the parallel multi battery pack is initiated, receive a switch voltage value from a voltage sensor coupled to a k th sequence switch unit, where k is a turn-on sequence index, which is a natural number of 2 to n, before turning on the k th sequence switch unit, then turn on the k th sequence switch unit, subsequently receive a switch current value from a current sensor connected to the k th sequence switch unit, and count a watt energy value consumed in the k th sequence switch unit from the switch voltage value and the switch current value, and determine the turn-on sequence of the first to n th switch units (S1-Sn) in descending order from a switch unit having a greatest watt energy count value by referring to watt energy count values respectively corresponding to the first to n th switch units before charging or discharging of the parallel multi battery pack is initiated.