An engine start control device comprising: a control valve (106, idle speed control valve (ISCV)) including a stepping motor which adjusts a gas flow rate of a gas channel provided so as to bypass a throttle valve of an engine; a starter motor capable of driving a crankshaft of the engine; and an ignition switch (IGSW) for activating the control unit; a start switch (STSW) for starting the engine with the help of the starter motor; and a control unit; wherein the control unit sets a target opening degree of the control valve (106, ISCV); and wherein the control unit controls an opening degree of the control valve as a change amount from an opening degree at an activation instant of the control unit to the target opening degree and wherein the control unit controls a current supply to the starter motor, when the start switch (STSW) is turned on and when the opening degree of the control valve (106, ISCV) has reached the target opening degree; characterized in that the engine start control device further comprises: a latch circuit which holds a command for current control from the control unit to the starter motor, wherein the latch circuit continues the current supply to the starter motor according to the command for current control that the latch circuit keeps holding, even when the control unit is reset during cranking by the starter motor; and reset determining means for determining whether or not the restored control unit is reset based on the command for current control held by the latch circuit; wherein the restored control unit fixes the opening degree of the control valve at an opening degree at the current moment in a case where the control unit is reset; and wherein the restored control unit controls the opening of the control valve (106, ISCV) to a new set target opening degree, if the activation of the control unit is not due to a reset. a control valve (106, idle speed control valve (ISCV)) including a stepping motor which adjusts a gas flow rate of a gas channel provided so as to bypass a throttle valve of an engine; a starter motor capable of driving a crankshaft of the engine; and an ignition switch (IGSW) for activating the control unit; a start switch (STSW) for starting the engine with the help of the starter motor; and a control unit; wherein the control unit sets a target opening degree of the control valve (106, ISCV); and wherein the control unit controls an opening degree of the control valve as a change amount from an opening degree at an activation instant of the control unit to the target opening degree and wherein the control unit controls a current supply to the starter motor, when the start switch (STSW) is turned on and when the opening degree of the control valve (106, ISCV) has reached the target opening degree; characterized in that the engine start control device further comprises: a latch circuit which holds a command for current control from the control unit to the starter motor, wherein the latch circuit continues the current supply to the starter motor according to the command for current control that the latch circuit keeps holding, even when the control unit is reset during cranking by the starter motor; and reset determining means for determining whether or not the restored control unit is reset based on the command for current control held by the latch circuit; wherein the restored control unit fixes the opening degree of the control valve at an opening degree at the current moment in a case where the control unit is reset; and a latch circuit which holds a command for current control from the control unit to the starter motor, wherein the latch circuit continues the current supply to the starter motor according to the command for current control that the latch circuit keeps holding, even when the control unit is reset during cranking by the starter motor; and reset determining means for determining whether or not the restored control unit is reset based on the command for current control held by the latch circuit; wherein the restored control unit fixes the opening degree of the control valve at an opening degree at the current moment in a case where the control unit is reset; and wherein the restored control unit controls the opening of the control valve (106, ISCV) to a new set target opening degree, if the activation of the control unit is not due to a reset.