A liquid supply device comprising: a first reservoir configured to store a first liquid; a second reservoir configured to store a second liquid; a first tank positioned lower than the first reservoir, wherein an outer shape of the first tank can change between an expanded state and a contracted state depending on an amount of the first liquid stored therein; a second tank positioned lower than the second reservoir, wherein an outer shape of the second tank can change between an expanded state and a contracted state depending on an amount of the second liquid stored therein; a first valve configured to open and close a first channel connecting the first reservoir and the first tank; a second valve configured to open and close a second channel connecting the second reservoir and the second tank; a head, wherein the liquid supply device is configured such that the first liquid is capable of flowing into the head from the first tank through a third channel, and the second liquid is capable of flowing into the head from the second tank through a fourth channel; a suction mechanism configured to apply a suction pressure to the third channel and the fourth channel from a head side of the third channel and the fourth channel, wherein the head side is the side at which the head is positioned; a first sensor; a second sensor; and a controller, wherein the controller is configured to: execute a valve-opening operation of opening the first valve and the second valve, in response to receiving of a suction instruction; execute, after executing the valve-opening operation, a valve-closing operation of closing the first valve in response to receiving of a first signal from the first sensor, and closing the second valve in response to receiving of a second signal from the second sensor, the first signal being a signal indicating that an amount of the first liquid in the first tank is a first threshold value or more, the second signal being a signal indicating that an amount of the second liquid in the second tank is a second threshold value or more; and execute, after executing the valve-closing operation, a suction operation of driving the suction mechanism for a predetermined time period. a first reservoir configured to store a first liquid; a second reservoir configured to store a second liquid; a first tank positioned lower than the first reservoir, wherein an outer shape of the first tank can change between an expanded state and a contracted state depending on an amount of the first liquid stored therein; a second tank positioned lower than the second reservoir, wherein an outer shape of the second tank can change between an expanded state and a contracted state depending on an amount of the second liquid stored therein; a first valve configured to open and close a first channel connecting the first reservoir and the first tank; a second valve configured to open and close a second channel connecting the second reservoir and the second tank; a head, wherein the liquid supply device is configured such that the first liquid is capable of flowing into the head from the first tank through a third channel, and the second liquid is capable of flowing into the head from the second tank through a fourth channel; a suction mechanism configured to apply a suction pressure to the third channel and the fourth channel from a head side of the third channel and the fourth channel, wherein the head side is the side at which the head is positioned; a first sensor; a second sensor; and a controller, wherein the controller is configured to: execute a valve-opening operation of opening the first valve and the second valve, in response to receiving of a suction instruction; execute, after executing the valve-opening operation, a valve-closing operation of closing the first valve in response to receiving of a first signal from the first sensor, and closing the second valve in response to receiving of a second signal from the second sensor, the first signal being a signal indicating that an amount of the first liquid in the first tank is a first threshold value or more, the second signal being a signal indicating that an amount of the second liquid in the second tank is a second threshold value or more; and execute a valve-opening operation of opening the first valve and the second valve, in response to receiving of a suction instruction; execute, after executing the valve-opening operation, a valve-closing operation of closing the first valve in response to receiving of a first signal from the first sensor, and closing the second valve in response to receiving of a second signal from the second sensor, the first signal being a signal indicating that an amount of the first liquid in the first tank is a first threshold value or more, the second signal being a signal indicating that an amount of the second liquid in the second tank is a second threshold value or more; and execute, after executing the valve-closing operation, a suction operation of driving the suction mechanism for a predetermined time period.