An electronic pen (1, 1M, 1C, 1D, 1S) that is configured to transmit a signal to a sensor of a position detecting device, the electronic pen (1, 1M, 1C, 1D, 1S) including: a core body; and a signal transmitting unit that is configured to transmit at least one signal to the sensor; the electronic pen being characterized in that the electronic pen (1, 1M, 1C, 1D, 1S) further includes: a protection mechanism that is configured to set at least a tip of the core body to a state of being not exposed to external to protect at least the tip of the core body; and detecting means that is configured to detect whether or not at least the tip of the core body is in a state of being protected by the protection mechanism, wherein based on a detection result of the detecting means, a signal for position detection and a signal including additional information that are to be transmitted to the position detecting device when position indication operation is carried out over the sensor are allowed to be transmitted from the signal transmitting unit when at least the tip of the core body is not protected by the protection mechanism and is exposed to the external, and the signal including the additional information is precluded from being transmitted when at least the tip of the core body is protected by the protection mechanism, and wherein the signal for position detection is sent out and the signal including the additional information is precluded from being transmitted when at least the core body is protected by the protection mechanism. a core body; and a signal transmitting unit that is configured to transmit at least one signal to the sensor; the electronic pen being characterized in that the electronic pen (1, 1M, 1C, 1D, 1S) further includes: a protection mechanism that is configured to set at least a tip of the core body to a state of being not exposed to external to protect at least the tip of the core body; and detecting means that is configured to detect whether or not at least the tip of the core body is in a state of being protected by the protection mechanism, a protection mechanism that is configured to set at least a tip of the core body to a state of being not exposed to external to protect at least the tip of the core body; and detecting means that is configured to detect whether or not at least the tip of the core body is in a state of being protected by the protection mechanism, wherein based on a detection result of the detecting means, a signal for position detection and a signal including additional information that are to be transmitted to the position detecting device when position indication operation is carried out over the sensor are allowed to be transmitted from the signal transmitting unit when at least the tip of the core body is not protected by the protection mechanism and is exposed to the external, and the signal including the additional information is precluded from being transmitted when at least the tip of the core body is protected by the protection mechanism, and wherein the signal for position detection is sent out and the signal including the additional information is precluded from being transmitted when at least the core body is protected by the protection mechanism.