A non-contact information processing device comprising: non-contact information processing means for recording and/or reproducing information through electromagnetic induction without contacting the card medium, wherein the non-contact information processing means has a device-side non-contact communication antenna, that is able to send and receive information to/from a medium-side non-contact communication antenna provided on the card medium, and a control circuit for controlling the device-side non-contact communication antenna; and detection means, which detects if the device-side non-contact communication antenna is working normally, and has a control section, being independent of said control circuit, and detects an electromagnetic wave sent from the device-side non-contact communication antenna to the medium-side non-contact communication antenna provided on the card medium when the device-side non-contact communication antenna sends and receives information to/from the medium-side non-contact communication antenna; characterized in that a transfer path is provided for transferring the card medium; said device-side non-contact communication antenna is able to send and receive information to/from said medium-side non-contact communication antenna provided on the card medium when the card medium arrives at a predetermined position in said transfer path; and the detection means has an electromagnetic wave detection antenna for detecting an electromagnetic wave generated from the device-side non-contact communication antenna, and an electromagnetic wave detection LED for visually checking if the device-side non-contact communication antenna is working normally, wherein the electromagnetic wave detection antenna is placed at a position between the device-side non-contact communication antenna and the medium-side non-contact communication antenna when the device-side non-contact communication antenna sends and receives information to/from the medium-side non-contact communication antenna, and wherein the control section is equipped with a rectifier circuit for rectifying a current obtained through the electromagnetic wave detection antenna, and supplying the rectified current to the electromagnetic wave detection LED. non-contact information processing means for recording and/or reproducing information through electromagnetic induction without contacting the card medium, wherein the non-contact information processing means has a device-side non-contact communication antenna, that is able to send and receive information to/from a medium-side non-contact communication antenna provided on the card medium, and a control circuit for controlling the device-side non-contact communication antenna; and detection means, which detects if the device-side non-contact communication antenna is working normally, and has a control section, being independent of said control circuit, and detects an electromagnetic wave sent from the device-side non-contact communication antenna to the medium-side non-contact communication antenna provided on the card medium when the device-side non-contact communication antenna sends and receives information to/from the medium-side non-contact communication antenna; characterized in that a transfer path is provided for transferring the card medium; said device-side non-contact communication antenna is able to send and receive information to/from said medium-side non-contact communication antenna provided on the card medium when the card medium arrives at a predetermined position in said transfer path; and the detection means has an electromagnetic wave detection antenna for detecting an electromagnetic wave generated from the device-side non-contact communication antenna, and an electromagnetic wave detection LED for visually checking if the device-side non-contact communication antenna is working normally, wherein the electromagnetic wave detection antenna is placed at a position between the device-side non-contact communication antenna and the medium-side non-contact communication antenna when the device-side non-contact communication antenna sends and receives information to/from the medium-side non-contact communication antenna, and wherein the control section is equipped with a rectifier circuit for rectifying a current obtained through the electromagnetic wave detection antenna, and supplying the rectified current to the electromagnetic wave detection LED.