A transfer device (10) for transferring a fluid from a container having a body with an open first end and a piston within the body, the transfer device (10) comprising an outer housing (26) which is designed to receive a cartridge assembly (32) which includes the container, a plunger rod (24) aligned with the piston in the body, a spring (22) positioned to drive the plunger rod (24) in a direction towards the piston, a retractor (28) to move the plunger rod (24) from an activated position wherein the spring (22) is extended to a non- activated position wherein the spring is compressed, and an actuator (92) to permit the spring to be released to drive the plunger rod (24) to move the piston within the container body. Typically, the device is used for transferring fluid from one container to a further container.