The invention discloses a deposition substance monitoring device and a vacuum pump for correctly determining whether a deposition amount is excessive. The deposition substance monitoring part (25) comprises: a state determination part (252) configured to determine whether or not a vacuum pump main body is in a predetermined exhaust state or to determine the pump main body is either in a ventilation state or in a barely-no-flow state; and a determination part (252) configured to receive a deposition amount indicator (motor current value) for an amount of a deposition substance in the pump to determine as excessive deposition when the deposition amount indicator in the predetermined exhaust state is equal to or greater than an acceptable deposition threshold.