A system comprising: a dental syringe (S); and a dental syringe holder , comprising: a syringe holding portion that attachably and detachably holds an outer barrel of the dental syringe (S); and a clamping wing portion that is formed on an outer periphery of the syringe holding portion , and is configured to be clamped by a forefinger and a middle finger in the case of holding the dental syringe (S) with three fingers that are the thumb, the forefinger and a middle finger in such a manner as to hold a pen, and a placing wing portion which is formed on the outer periphery of the syringe holding portion , and is configured so as to allow a thumb to be placed on it in the case of holding the dental syringe (S) with three fingers that are the thumb, the forefinger and a middle finger in such a manner as to hold a pen, wherein in a projected image on a plane orthogonal to an axial direction (AD) of the syringe (S), an angle (θ) that is formed by a first line segment (L1) connecting a center (C) of a minimum virtual circle (V) that surrounds the outer periphery of the syringe holding portion and a formation position (P1) of the clamping wing portion , and a second line segment (L2) connecting the center (C) of the virtual circle (V) and a formation position (P2) of the placing wing portion is in a range from 90° to 170° inclusive. a dental syringe (S); and a dental syringe holder , comprising: a syringe holding portion that attachably and detachably holds an outer barrel of the dental syringe (S); and a clamping wing portion that is formed on an outer periphery of the syringe holding portion , and is configured to be clamped by a forefinger and a middle finger in the case of holding the dental syringe (S) with three fingers that are the thumb, the forefinger and a middle finger in such a manner as to hold a pen, and a placing wing portion which is formed on the outer periphery of the syringe holding portion , and is configured so as to allow a thumb to be placed on it in the case of holding the dental syringe (S) with three fingers that are the thumb, the forefinger and a middle finger in such a manner as to hold a pen, a syringe holding portion that attachably and detachably holds an outer barrel of the dental syringe (S); and a clamping wing portion that is formed on an outer periphery of the syringe holding portion , and is configured to be clamped by a forefinger and a middle finger in the case of holding the dental syringe (S) with three fingers that are the thumb, the forefinger and a middle finger in such a manner as to hold a pen, and a placing wing portion which is formed on the outer periphery of the syringe holding portion , and is configured so as to allow a thumb to be placed on it in the case of holding the dental syringe (S) with three fingers that are the thumb, the forefinger and a middle finger in such a manner as to hold a pen, wherein in a projected image on a plane orthogonal to an axial direction (AD) of the syringe (S), an angle (θ) that is formed by a first line segment (L1) connecting a center (C) of a minimum virtual circle (V) that surrounds the outer periphery of the syringe holding portion and a formation position (P1) of the clamping wing portion , and a second line segment (L2) connecting the center (C) of the virtual circle (V) and a formation position (P2) of the placing wing portion is in a range from 90° to 170° inclusive. <EOS>