Present disclosure provides a portable viscometer including a body and a measuring unit disposed on one side of the body. The measuring unit includes a capillary tube detachably attached to the measuring unit, and a first sensor and a second sensor, the first and second sensors being disposed adjacent to the capillary tube and vertically spaced apart from each other, and the capillary tube includes a bead therein. The bead may be fixed on the inner surface of the capillary tube by a fixing compound which is soluble in a fluid to be measured.