To provide a motor-operated circular saw apparatus enabling a worker to know the cut end position of a rotary saw blade which is invisible from the worker since covered by a safety cover and capable of accurately cutting a work at a predetermined position.

This motor-operated circular saw apparatus comprises a motor-operated round saw and a marking tool 3 for indicating the cut end position of the rotary saw blade 8. The motor-operated round saw comprises a motor 9, the rotary saw blade 8, a transmission means 7 for transmitting the rotation of the motor to the rotary saw blade 8, and a handle 6. The motor-operated round saw is integrally mounted on a support base 1. The marking tool 3 for indicating the cut end position of the rotary saw blade 8 is movably provided to the support base 1.