PURPOSE: To execute evenly and uniformly a titled test, and to prevent an action of an unexpected undesirable force by controlling a titled device so that displacement of each part of a structure by driving of plural force applying jacks coincides with a target value.

CONSTITUTION: Plural force applying jacks 11...11 are installed to a structure W to be tested, and plural displacement sensors 12...12 for detecting displacement of each part of the structure W are provided in accordance with each of them. Driving of each force applying jack is controlled by an operating signal generated from corresponding jack control devices 13...13. Magnitude of said each operating signal is determined by a value of each control instruction Ai. Each displacement sensor is constituted of a magnetic lattice scale and a magnetic head, and its output is led into a displacement counter 14. An operation control part 15 calculates successively the control instruction Ai to be supplied to each jack control device 13...13 in accordance with a program, from a displacement detected value Si of its each part, a displacement target value Mio set in advance, the number of divisions N, etc.