A circuit-substrate-related-work assisting device configured to assist a circuit-substrate-related work performed by a circuit-substrate-related-work performing machine (24, 30, 38) on a circuit substrate that constitutes an electric circuit, comprising: a quality judging portion configured to make a judgment as to a change in work quality of the circuit-substrate-related-work performing machine (24, 30, 38); an improvement-action determining portion configured to determine an improvement action for improving the work quality where the quality judging portion judges that a degree of deterioration of the work quality exceeds a prescribed degree; an action notifying portion configured to notify at least one of the circuit-substrate-related-work performing machine (24, 30, 38) and an operator of the circuit-substrate-related-work performing machine (24, 30, 38) of the improvement action determined by the improvement-action determining portion; and an action-completion-information receiving portion configured to receive, from at least one of the circuit-substrate-related-work performing machine (24, 30, 38) and the operator, action-completion information that is information as to completion of the improvement action notified by the action notifying portion, wherein the quality judging portion is configured to judge whether the circuit substrate is the circuit substrate on which the circuit substrate related work was performed after implementation of the improvement action and to make a judgment as to a change in the work quality before and after the completion of the improvement action, conditionally on reception of the action-completion information by the action-completion-information receiving portion, the improvement-action determining portion is configured to determine another improvement action different from the determined improvement action where there are no signs of improvement in the work quality even though the determined improvement action has been implemented on the circuit-substrate-related-work performing machine (24, 30, 38), and the improvement-action determining portion is configured to determine said another improvement action according to a priority order set in advance. a quality judging portion configured to make a judgment as to a change in work quality of the circuit-substrate-related-work performing machine (24, 30, 38); an improvement-action determining portion configured to determine an improvement action for improving the work quality where the quality judging portion judges that a degree of deterioration of the work quality exceeds a prescribed degree; an action notifying portion configured to notify at least one of the circuit-substrate-related-work performing machine (24, 30, 38) and an operator of the circuit-substrate-related-work performing machine (24, 30, 38) of the improvement action determined by the improvement-action determining portion; and an action-completion-information receiving portion configured to receive, from at least one of the circuit-substrate-related-work performing machine (24, 30, 38) and the operator, action-completion information that is information as to completion of the improvement action notified by the action notifying portion, wherein the quality judging portion is configured to judge whether the circuit substrate is the circuit substrate on which the circuit substrate related work was performed after implementation of the improvement action and to make a judgment as to a change in the work quality before and after the completion of the improvement action, conditionally on reception of the action-completion information by the action-completion-information receiving portion, the improvement-action determining portion is configured to determine another improvement action different from the determined improvement action where there are no signs of improvement in the work quality even though the determined improvement action has been implemented on the circuit-substrate-related-work performing machine (24, 30, 38), and the improvement-action determining portion is configured to determine said another improvement action according to a priority order set in advance.