To provide an abnormality alarm device for a transmitter capable of accurately detecting fluctuation of a loop resistance.

The abnormality alarm device for a transmitter connected to a DC power supply via a loop resistance for outputting a loop current related to a process quantity to the loop resistance, includes: threshold calculation means for calculating an allowable threshold for voltage fluctuation between terminals of the transmitter in a current measured value of the loop current on the basis of the current measured value of the loop current and a tolerance set value of the loop resistance; reference-voltage-between-terminals generation means for generating a reference voltage between terminals in the current loop current according to logical characteristics of a voltage between terminals based on a supply voltage of the DC power supply and a reference value of the loop resistance; and alarm means for being input a current voltage measured value between the terminals of the transmitter, the reference voltage between terminals, and the allowable threshold, and outputting an abnormality alarm of the loop resistance when a difference between the voltage measured value between the terminals and the reference voltage between terminals is over the allowable threshold.