A power transmission device configured to transmit power in a noncontact manner to an instrument ; the instrument comprising a first case , a power reception coil arranged to generate an induced current due to magnetic flux in a first direction intersecting a gravitational direction, and a holder configured to hold the power reception coil at a predetermined distance from an outer surface of the first case in the first case ; the power transmission device comprising: a conductive second case having an opening into which the instrument can be inserted and in which the instrument can be stored; a power transmission coil formed on a printed circuit board and disposed in the second case so as to generate magnetic flux in the first direction, and arranged to generate an induced current in the power reception coil ; and an elastic body disposed in the second case , and arranged to maintain a distance between the power transmission coil and the power reception coil to be constant, and to support the power transmission coil ; a sensor configured to detect a position of the power transmission coil , the sensor comprising a first sensor and a second sensor disposed at both ends inside the second case , the first sensor and the second sensor configured to detect a position of the printed circuit board ; wherein the second case has a case surface on which LED are provided and wherein the LED are configured to be lit so as to indicate that the power transmission coil and the power reception coil are located at positions suitable for noncontact power transmission; a controller configured to control the LED to indicate that the power reception coil is chargeable by the power transmission coil when the output from both the first sensor and the second sensor indicates that the power reception coil and the power transmission coil are at a position suitable for noncontact power transmission. a conductive second case having an opening into which the instrument can be inserted and in which the instrument can be stored; a power transmission coil formed on a printed circuit board and disposed in the second case so as to generate magnetic flux in the first direction, and arranged to generate an induced current in the power reception coil ; and an elastic body disposed in the second case , and arranged to maintain a distance between the power transmission coil and the power reception coil to be constant, and to support the power transmission coil ; a sensor configured to detect a position of the power transmission coil , the sensor comprising a first sensor and a second sensor disposed at both ends inside the second case , the first sensor and the second sensor configured to detect a position of the printed circuit board ; wherein the second case has a case surface on which LED are provided and wherein the LED are configured to be lit so as to indicate that the power transmission coil and the power reception coil are located at positions suitable for noncontact power transmission; a controller configured to control the LED to indicate that the power reception coil is chargeable by the power transmission coil when the output from both the first sensor and the second sensor indicates that the power reception coil and the power transmission coil are at a position suitable for noncontact power transmission. <EOS>