A concrete mixer truck having a mixer drum capable of carrying freshly mixed concrete, comprising: a driving device that is driven by rotation of an engine so as to drive the mixer drum to rotate using a fluid pressure of a working fluid; a pressure detector that detects a pressure of the working fluid in the driving device; and a controller having a material introduction determination unit that is adapted to determines whether or not a material for generating the freshly mixed concrete has been introduced into the mixer drum; wherein the controller further has a pressure determination unit that is adapted to determines whether or not the pressure of the working fluid detected by the pressure detector has fallen to a set pressure set in advance in accordance with a carrying amount and a fluidity of the freshly mixed concrete after the introduction of the materials for the freshly mixed concrete into the mixer drum and the concrete mixer truck further comprises a notification device that is adapted to notify an operator that the pressure of the working fluid in the driving device has fallen to the set pressure on the basis of the determination made by the pressure determination unit. wherein, in a steady state, the driving device drives the mixer drum to perform agitation rotation, which is rotation at a rotation speed at which a quality of the freshly mixed concrete in the mixer drum can be maintained the material introduction determination unit determines whether or not the material has been introduced into the mixer drum on the basis of the pressure of the working fluid detected by the pressure detector and the controller is adapted to switch the rotation of the mixer drum to mixing rotation, which is rotation at a higher speed than the agitation rotation, when the material introduction determination unit determines that the material has been introduced into the mixer drum, and wherein the controller is adapted to switch rotation of the mixer drum to the agitation rotation, when the pressure determination unit determines that the pressure of the working fluid in the driving device has fallen to the set pressure. a driving device that is driven by rotation of an engine so as to drive the mixer drum to rotate using a fluid pressure of a working fluid; a pressure detector that detects a pressure of the working fluid in the driving device; and a controller having a material introduction determination unit that is adapted to determines whether or not a material for generating the freshly mixed concrete has been introduced into the mixer drum; wherein the controller further has a pressure determination unit that is adapted to determines whether or not the pressure of the working fluid detected by the pressure detector has fallen to a set pressure set in advance in accordance with a carrying amount and a fluidity of the freshly mixed concrete after the introduction of the materials for the freshly mixed concrete into the mixer drum and the concrete mixer truck further comprises a notification device that is adapted to notify an operator that the pressure of the working fluid in the driving device has fallen to the set pressure on the basis of the determination made by the pressure determination unit. wherein, in a steady state, the driving device drives the mixer drum to perform agitation rotation, which is rotation at a rotation speed at which a quality of the freshly mixed concrete in the mixer drum can be maintained the material introduction determination unit determines whether or not the material has been introduced into the mixer drum on the basis of the pressure of the working fluid detected by the pressure detector and the controller is adapted to switch the rotation of the mixer drum to mixing rotation, which is rotation at a higher speed than the agitation rotation, when the material introduction determination unit determines that the material has been introduced into the mixer drum, and wherein the controller is adapted to switch rotation of the mixer drum to the agitation rotation, when the pressure determination unit determines that the pressure of the working fluid in the driving device has fallen to the set pressure.