PURPOSE: To prevent a saw blade from being largely broken, by providing such an arragement that an actual cutting power is compared with a normal cutting power which is computed in view of the specification of a pipe to be cut and the specification of a saw blade to detect an abnormality.

CONSTITUTION: Referring to a block diagram indicating an abnormal cutting condition detecting device in a saw cutter, a pipe cutting length computing circuit 17 calculates a pipe cutting length at each blade feed position in accordance with the specification of a pipe to be cut, which is set by specification setting units 18, 19, 20, and the maximum value maxL of the cutting length is delivered to a cutting power computing circuit 23. By setting a number on the pipe kind setting unit 22, one of specific cutting resistances R which are previously sorted with numbers, is red out, and is delivered to a cutting power computing circuit 23. Then, a necessary cutting power maxP obtained in the circuit 23 is compared with a power Q which is fed to a motor and which is measured, in an abnormal detecting circuit 26. Thus, by detecting a cutting abnormality at an early stage, a saw blade may be prevented from being largely broken.