A viscous fluid supply device (10, 50) comprising: a housing (53, 63, 66); a movable member arranged inside the housing (53, 63, 66) in a state maintaining airtightness and so as to be movable in accordance with a pressure level inside an air chamber; an ejection nozzle configured to eject a viscous fluid filled between the housing (53, 63, 66) and the movable member in accordance with movement of the movable member inside the housing (53, 63, 66); a pressure adjusting device configured to apply pressure to the air chamber so as to move the movable member inside the housing (53, 63, 66), the viscous fluid being supplied from the ejection nozzle by pressure being applied to the air chamber by the pressure adjusting device; a control device (100, 101) configured to control operation related to supply of the viscous fluid via the ejection nozzle; and a pressure sensor configured to detect whether the pressure inside the air chamber has reached a specified set pressure, wherein the control device (100, 101) includes a pressure adjusting control section configured to control operation of the pressure adjusting device so as to decrease the pressure inside the air chamber when supply of the viscous fluid from the ejection nozzle has been stopped, characterized by: a time measuring control section configured to measure a required time from starting to decrease the pressure inside the air pressure using the pressure adjusting device to when the pressure sensor detects that the pressure inside the air chamber has been reduced to the set pressure, and a remaining amount estimating control section configured to estimate a remaining amount of the viscous fluid based on a measurement result of the required time measured by the time measuring control section. a housing (53, 63, 66); a movable member arranged inside the housing (53, 63, 66) in a state maintaining airtightness and so as to be movable in accordance with a pressure level inside an air chamber; an ejection nozzle configured to eject a viscous fluid filled between the housing (53, 63, 66) and the movable member in accordance with movement of the movable member inside the housing (53, 63, 66); a pressure adjusting device configured to apply pressure to the air chamber so as to move the movable member inside the housing (53, 63, 66), the viscous fluid being supplied from the ejection nozzle by pressure being applied to the air chamber by the pressure adjusting device; a control device (100, 101) configured to control operation related to supply of the viscous fluid via the ejection nozzle; and a pressure sensor configured to detect whether the pressure inside the air chamber has reached a specified set pressure, wherein the control device (100, 101) includes a pressure adjusting control section configured to control operation of the pressure adjusting device so as to decrease the pressure inside the air chamber when supply of the viscous fluid from the ejection nozzle has been stopped, a time measuring control section configured to measure a required time from starting to decrease the pressure inside the air pressure using the pressure adjusting device to when the pressure sensor detects that the pressure inside the air chamber has been reduced to the set pressure, and a remaining amount estimating control section configured to estimate a remaining amount of the viscous fluid based on a measurement result of the required time measured by the time measuring control section.