A control system controls a construction machine that includes a work machine including a bucket having a plurality of tilting mechanisms. The control system includes: a tilt angle sensor that is provided in the bucket so as to detect tilt angle data including a rotation angle of the bucket about the tilt shaft, the tilt angle sensor being capable of detecting an inclination angle with respect to a horizontal plane; a data acquisition unit to which the tilt angle data is output from the tilt angle sensor; a data fixing unit that fixes the tilt angle data output to the data acquisition unit based on a fixing command to generate fixed data; and a work machine control unit that controls the work machine based on the fixed data until the fixing command is disabled.