Aspects of the invention can provide a lamp device that is capable of avoiding concentration of stresses in a sub-mirror fixing portion of an arc tube. The lamp device can include an arc tube provided with a bulb portion encapsulating inside a pair of electrodes, and a pair of sealing portions formed continuously from the bulb portion and sealing inside electrode axes having the electrodes at tip ends and conductor foils to bring the electrode axes into conduction, a main reflection mirror, to which the sealing portion is fixed, to reflect lights emitted from the arc tube toward an illuminated region, and a sub-mirror fixed to the sealing portion in such a manner that a reflection surface opposes the main reflection mirror with the bulb portion in between. The sub-mirror can be bonded with a bonding agent to a surface region of the sealing portion present in a direction moving away from the bulb portion in reference to a position corresponding to a termination of the electrode axis.