PURPOSE: To make it possible to continuously control the running speed of a container processing means and that of a conveyor according to the amount of storage of containers by computing and measuring the amount of storage of containers according to pressures detected by a pressure detecting means for detecting the advancing forces of containers.

CONSTITUTION: A pressure detecting means 11 for detecting the advancing forces of containers 2 is provided upstream of a container processing means 4, and the amount of storage of containers 2 is computed and measured according to the detected pressure; that is, each container 2, which is to be stored upstream of the container processing means 4, is stored while abutting against each other and sliding against the conveyor 1 and, since its advancing forces are substantially proportional to the amount of storage of containers, the amount of storage of containers 2 can be computed and measured by detection of the advancing forces of containers 2 by the pressure detecting means 11. It is thus enabled to continuously control the running speed of the container processing means 4 and that of the conveyor 1 according to the amount of storage of containers 2.