The invention provides a detection device and a detection method, which are used to detect the step pitch of a material rack for transferring materials in the process of SMT operation. The detection method comprises the following steps: acquiring the transfer time of a material belt in a material rack in each SMT operation and taking the transfer time as the detection period; installing a to-be-detected element doing circular motion along with a gear on the gear used for transferring the material belt, and setting a detection circuit board used for detecting the to-be-detected element near the gear; if the detection circuit board detects the to-be-detected element in the detection period, judging that the step pitch of the material rack is normal; and if the detection circuit board fails to detect the to-be-detected element in the detection period, judging that the step pitch of the material rack is wrong. The purpose of automatic detection can be achieved. Material loss caused by wrong setting of the step pitch of materials by SMT workers in the feeding process is prevented effectively.