A calibration sensor unit for calibrating an eyeglass lens processing apparatus including a lens chuck shaft (102R, 102L) extending in a first direction for holding an eyeglass lens, a processing tool (163, 221 a, 221 b, 436) for processing a peripheral edge of the lens and a processing tool rotating shaft (161 a, 230, 431) to which the processing tool is attached, the calibration sensor unit comprising: an attachment portion configured to be attached to the lens chuck shaft; a contact member configured to contact the processing tool; characterized by: a support mechanism configured to support the contact member so as to be movable in a second direction orthogonal to the first direction when the attachment portion is attached to the lens chuck shaft; a sensor configured to detect the contact of the contact member with the processing tool; and a signal transmitting portion configured to transmit a detecting signal of the sensor to the eyeglass lens processing apparatus, wherein the support mechanism includes an urging member configured to urge the contact member in a direction separating from the attachment portion, the urging member has an urging force by which the processing tool rotating shaft and the lens chuck shaft are not bent to a predetermined tolerance or more when the contact member contacts the processing tool and is moved toward the attachment portion, and wherein the sensor is provided at one of the contact member and the attachment portion and arranged in such a position that the sensor can detect that the contact member is moved toward the attachment portion against the urging force of the urging member. an attachment portion configured to be attached to the lens chuck shaft; a contact member configured to contact the processing tool; characterized by: a support mechanism configured to support the contact member so as to be movable in a second direction orthogonal to the first direction when the attachment portion is attached to the lens chuck shaft; a sensor configured to detect the contact of the contact member with the processing tool; and a signal transmitting portion configured to transmit a detecting signal of the sensor to the eyeglass lens processing apparatus, a support mechanism configured to support the contact member so as to be movable in a second direction orthogonal to the first direction when the attachment portion is attached to the lens chuck shaft; a sensor configured to detect the contact of the contact member with the processing tool; and a signal transmitting portion configured to transmit a detecting signal of the sensor to the eyeglass lens processing apparatus, wherein the support mechanism includes an urging member configured to urge the contact member in a direction separating from the attachment portion, the urging member has an urging force by which the processing tool rotating shaft and the lens chuck shaft are not bent to a predetermined tolerance or more when the contact member contacts the processing tool and is moved toward the attachment portion, and wherein the sensor is provided at one of the contact member and the attachment portion and arranged in such a position that the sensor can detect that the contact member is moved toward the attachment portion against the urging force of the urging member.