A screen image generation method for generating a management screen image indicating a state of a facility (M1, M2, M3, M4, Mn) in a production plant, the method comprising: - first acquisition of acquiring first data concerning the facility (M1, M2, M3, M4, Mn) and transmitted from a sensor (C11, C12, C21, Cn1) accompanying the facility (M1, M2, M3, M4, Mn); - second acquisition of acquiring second data concerning the facility (M1, M2, M3, M4, Mn) and transmitted from a controller (P1, P2, Pn) incorporated in the facility (M1, M2, M3, M4, Mn); - third acquisition of acquiring, in real time, an alert concerning the facility (M1, M2, M3, M4, Mn) irregularly transmitted from the controller (P1, P2, Pn) incorporated in the facility (M1, M2, M3, M4, Mn); and - generating a management screen image indicating the state of the facility (M1, M2, M3, M4, Mn) in accordance with the first data, the second data, and the alert; wherein - the first acquisition, the second acquisition, the third acquisition, and the generating the management screen image are performed by one or more processors via a gateway disposed inside the production plant, the one or more processors being included in a server, - a master sensor connected to the sensor (C11, C12, C21, Cn1) regularly transmits the first data to the gateway at intervals of a first time, - the one or more processors regularly acquires the first data from the gateway at intervals of a second time shorter than the first time in the first acquisition, - the controller (P1, P2, Pn) transmits, to the gateway, the second data irregularly, or regularly at intervals of a third time shorter than the second time, - the one or more processors regularly acquires, from the gateway, the second data accumulated in the gateway at intervals of the second time in the second acquisition processing, and - the one or more processors keeps updated the state of the facility (M1, M2, M3, M4, Mn) indicated in the management screen image by repeatedly performing the generation at intervals of a fourth time equal to or shorter than the second time. - first acquisition of acquiring first data concerning the facility (M1, M2, M3, M4, Mn) and transmitted from a sensor (C11, C12, C21, Cn1) accompanying the facility (M1, M2, M3, M4, Mn); - second acquisition of acquiring second data concerning the facility (M1, M2, M3, M4, Mn) and transmitted from a controller (P1, P2, Pn) incorporated in the facility (M1, M2, M3, M4, Mn); - third acquisition of acquiring, in real time, an alert concerning the facility (M1, M2, M3, M4, Mn) irregularly transmitted from the controller (P1, P2, Pn) incorporated in the facility (M1, M2, M3, M4, Mn); and - generating a management screen image indicating the state of the facility (M1, M2, M3, M4, Mn) in accordance with the first data, the second data, and the alert; - the first acquisition, the second acquisition, the third acquisition, and the generating the management screen image are performed by one or more processors via a gateway disposed inside the production plant, the one or more processors being included in a server, - a master sensor connected to the sensor (C11, C12, C21, Cn1) regularly transmits the first data to the gateway at intervals of a first time, - the one or more processors regularly acquires the first data from the gateway at intervals of a second time shorter than the first time in the first acquisition, - the controller (P1, P2, Pn) transmits, to the gateway, the second data irregularly, or regularly at intervals of a third time shorter than the second time, - the one or more processors regularly acquires, from the gateway, the second data accumulated in the gateway at intervals of the second time in the second acquisition processing, and - the one or more processors keeps updated the state of the facility (M1, M2, M3, M4, Mn) indicated in the management screen image by repeatedly performing the generation at intervals of a fourth time equal to or shorter than the second time.