To provide a portable tool that facilitates a worker to judge whether the portable tool is in an overload condition or not independently of experience of the worker.
A control unit 18 of the portable tool compares a rotation frequency of a cutter blade 43 of the portable tool which is detected based on a signal from a rotation sensor 44 with a rotation frequency of an engine 15 which is detected based on a signal from a plug cord 15E (S6). If these are the same (S7: NO), one alarm lamp out of alarm lamps of an alarm lamp 19, is turned on to represent a condition that a load on the engine 15 is small (S8). If these are not the same (S7: YES), a difference between the rotation frequency of the engine 15 and the rotation frequency of the cutter blade 43 is calculated (S9) and the calculated difference value is compared with first and second rotation-frequency difference-values stored in a non-volatile memory (S10). If the calculated difference value is larger than the second rotation-frequency difference-value, the alarm lamp represent the condition that the load on the engine 15 is large (S11).
Shin Koizumi
Akiko Ichikawa
Kunihiko Wakabayashi