Apparatus for measuring the capacity of a container for explosive and/or inflammable substances; said apparatus comprising: • a laser measurement device, for generating a ray for the measurement of a distance; • at least one bearing shaft which extends along a longitudinal axis (k), to be inserted, at least partially, into the container; • a guide arranged along a direction that is parallel to longitudinal axis (k) of shaft; • an optic deflector, for deflecting said ray in a desired direction; • at least one electronic control device, for calculating the position of the optic deflector and to process the data obtained from said laser measurement device; • an actuating device, for moving: - said laser measurement device; - said actuating device itself; - said at least one bearing shaft; - at least one electronic control device; of the apparatus, in order to perform the measurement of the capacity of said container, said actuating device comprising: - at least one electric motor, - at least one mechanism; the apparatus being_ characterized in that: • said laser measurement device, said electronic control device, said guide and the electronic part of the actuating device are arranged outside of the container, and • the optic deflector is fixed to said bearing shaft. • said at least one motor and said at least one mechanism, of the actuating device, are able to: - cause said optic deflector to rotate around the longitudinal axis (k), rotating said shaft, and - to move the deflector itself along a direction that is parallel to the longitudinal axis (k) of the shaft, moving said laser measurement device, said bearing shaft, said electronic control device and actuating device itself, comprised in said apparatus, along said guide. • a laser measurement device, for generating a ray for the measurement of a distance; • at least one bearing shaft which extends along a longitudinal axis (k), to be inserted, at least partially, into the container; • a guide arranged along a direction that is parallel to longitudinal axis (k) of shaft; • an optic deflector, for deflecting said ray in a desired direction; • at least one electronic control device, for calculating the position of the optic deflector and to process the data obtained from said laser measurement device; • an actuating device, for moving: - said laser measurement device; - said actuating device itself; - said at least one bearing shaft; - at least one electronic control device; of the apparatus, in order to perform the measurement of the capacity of said container, - said laser measurement device; - said actuating device itself; - said at least one bearing shaft; - at least one electronic control device; of the apparatus, in order to perform the measurement of the capacity of said container, - at least one electric motor, - at least one mechanism; • said laser measurement device, said electronic control device, said guide and the electronic part of the actuating device are arranged outside of the container, and • the optic deflector is fixed to said bearing shaft. • said at least one motor and said at least one mechanism, of the actuating device, are able to: - cause said optic deflector to rotate around the longitudinal axis (k), rotating said shaft, and - to move the deflector itself along a direction that is parallel to the longitudinal axis (k) of the shaft, moving said laser measurement device, said bearing shaft, said electronic control device and actuating device itself, comprised in said apparatus, along said guide. - cause said optic deflector to rotate around the longitudinal axis (k), rotating said shaft, and - to move the deflector itself along a direction that is parallel to the longitudinal axis (k) of the shaft, moving said laser measurement device, said bearing shaft, said electronic control device and actuating device itself, comprised in said apparatus, along said guide.