To prevent a three-dimensional shape detecting device in a state of being unsuitable for detection of three-dimensional shape from performing the detection of three-dimensional shape.

An imaging apparatus 1 detects the imaging angle θp of the imaging device 1 in the imaging angle calculation section 612 by the use of a gravitational acceleration sensor 611, and determines whether the imaging angle θp exceeds a specified angle θpa by a state determination section 62. If the imaging angle exceeds the specified angle θpa, an alarm is raised with an alarm device 634 by an alarm generation section 633, a laser beam 70 is interrupted with a solenoid 632 by a solenoid driver circuit 631, to prevent a processor 40 from performing imaging processing. As the specified angle θpa is an angle at which a manuscript is put within the depth of field, and is an angle which does not make slit light emitted by the imaging device 1 proceed more upwards than a level, people around are not irradiated with the slit light, and excellent images are obtained.