The present invention relates to a device for automatic injection of a product into an injection site. The product is being carried by a container having a proximal open-end, a substantially closed distal end, carrying a needle to provide an outlet port for the product from the container and a piston provided in the container and distally movable with respect to the container. The movement of the piston causes the product to be expelled from the container. The device further comprises:automatic injection means for causing the piston to move with respect to the container；a housing receiving the automatic injection means；controlling means cooperating with the automatic injection means to produce an audible indicator when the piston is near the distal end of the container and the product is substantially completely expelled from the container thereby informing a user that injection of the product is completed；The present invention is characterized in that the controlling means comprise at least an intermediate part coupled to the automatic injection means and at least a flexible part coupled to the housing, the intermediate part cooperating with the flexible part to produce the audible indicator.
