Proposed is a dynamometer for measuring load of a rotary shaft to be tested, the dynamometer comprising: a dynamometer shaft connected to the rotary shaft to be tested; a casing part having a through hole through which the dynamometer shaft passes, and a water supply chamber and a drain chamber therein; a stator part including a first stator and a second stator to be spaced apart from each other; a toroidal chamber partitioning part partitioning a toroidal chamber into a first toroidal chamber and a second toroidal chamber, wherein the toroidal chamber partitioning part comprises a runner and a guide ring, forming a drain slot through which the fluid is discharged from the first toroidal chamber and the second toroidal chamber to the drain chamber; and a flow adjusting part adjusting flow rate of the fluid.