To provide a small-sized compact liquid supply device.

The liquid supply device, having a syringe pump constituted of a syringe internally containing a liquid and the piston sliding in the syringe, a tube connected to the syringe at one end part and a pusher for pushing the piston, is constituted so as to supply the liquid from the other end of the tube by pushing the piston by the pusher and supplying the liquid to the tube from the syringe. The liquid supply device is equipped with a support part for supporting the syringe, a linear moving mechanism arranged almost in parallel to the syringe pump and relatively moving the pusher linearly in the moving direction of the piston with respect to the support part and a pressure detection part arranged between the piston and the pusher and detecting the pressure produced by pushing the piston by the pusher, and further has a control part for controlling the operation of the linear moving mechanism on the basis of the pressure detected by the pressure detection part.