Instability of an internal state in a current-input-type delta-sigma modulator is reduced in a case where input changes sharply.
A signal current is input to a first integration node. A difference current between a fixed current and the signal current is input to a second integration node. A voltage-to-current converter that converts a difference voltage between the voltage of the first integration node and a first reference voltage into a current and outputs it is connected between the first integration node and the second integration node. The voltage of the second integration node is compared with a second reference voltage, and a 1-bit digital signal is output. Current is draws from the first integration node or the second integration node according to the 1-bit digital signal. A short-circuit switch is provided between the first integration node and the second integration node for short-circuiting them.